wanderbooks/plan/served.md

wanderbooks Served: the plan

Decisions of 2026-10-16

Stephen Waits made these decisions on 2026-10-16. Where anything below conflicts with them, they win, and the plan has been revised to match.

1. The books live hidden away, as you. Your computer gets no separate system account, no sudo and no containers. The books server runs as you, only while something you started is using it: the app, an agent session, or a terminal (amended 2026-10-18, D-21 and D-23: no background service). It keeps the books in a private folder that only your account can open, outside every project folder. Nothing the agent is told or shown ever names that folder. This means an agent cannot stumble into the books. An agent that went looking on purpose could still find them, and the books say so plainly ("same user, advisory"). Anyone who wants a hard wall runs the same server on another machine they control, such as a home server, a NAS or a rented server.
2. The viewer reads the books directly, read-only, as it does today. It never changes anything and never goes through the agent's connection. When the agent asks it to show you something, the request reaches the viewer through the books' own private folder, not through the agent's tools.
3. No extra pop-ups. Posting, closing and reconciling add no new permission prompts. The agent still shows you each entry before posting it, and a hidden check makes sure that what gets posted is exactly the preview the agent was given to show you.
4. Your own server now, a paid hosted service later. This plan builds the recipe for running the books on another machine you control, and claude.ai on the web can reach that machine. A hosted service for many customers is described separately at the end (section 11). This plan does not build it.
5. Decided by the engineer from the standards:
   • The company EIN is kept in the books' settings and shown masked.
   • Audits use the recommended review bar. The CPA package refuses to go out without a full counted audit unless a reason is given.
   • Odd-cent splits between members are tracked from the company's start.
   • New prepaid schedules are spread by the day.
   • During the re-audit, old reversals posted without their own receipt borrow the original entry's receipt.
   • The company's time zone is America/Denver.
   • Photographed receipts get no text recognition for now.
   • The CPA gets tax ID numbers through a one-time link that you send.
   • Emailing receipts in waits for the hosted service.
   • The test-only direct mode stays for tests and demos.
6. Three questions wait for the move to the server (P2):
   • Where should the automatic backups go?
   • Should the papers in the company/ folder be filed into the books?
   • Should the old copies of the books in the project folder move into the private folder? This is recommended, and nothing is deleted.
7. Light governance. The two-member LLC gets no consent paperwork, spending limits, signed memos or amendments. Decisions are recorded with who made them and when. Getting your go-ahead before household reimbursements is a note, not a lock on posting. Approval rules exist in the engine for other companies, but they stay off unless a company turns them on.
8. Plain language. Stephen reads the Summary and the User flows, so both are written in plain English.

---

Wanderbooks becomes a books server that owns its own data, and any agent can use the books from anywhere through the MCP. This plan starts from the winning proposal ("Served Books, built incrementally": ledger-mcp grows into the server in place). It adds the best ideas from the "Books as a Tenant" proposal (B) and the "One MCP, any agent" proposal (C), fixes every weakness and decision violation the three judges named, and states each resolution.

Paths are relative to /home/swaits/Code/wanderbooks/crates/ unless they are absolute. S: means ledger-mcp/src/server.rs. These references were spot-checked against the source: INSTRUCTIONS S:57, lock() with a std MutexGuard at S:553, open_vault S:521, redact_refusal S:870, today() S:1943, import_local_file S:4511, call_tool S:8160, get_info S:8171, cash_flow ledger-core/src/reports.rs:1231 with the "Owner distributions" label at :1437, split_first ledger-core/src/shares.rs:197, apportion ledger-core/src/kernel.rs:309, built_in_gain ledger-core/src/assets.rs:204, 20 #[kani::proof] in ledger-core/src/proofs.rs, and verify/lean/Wanderbooks/{Apportion,Statements,Ledger}.lean. This session's own copy of the wanderbooks instructions arrived cut off at "Prepaid expenses and deferred revenue: record the original… [truncated]", which confirms the 4,096-character client limit.

---

1. Summary

Today. Your books are a folder inside your project directory. That folder holds the journal, the receipts, the settings, a list of helper commands and the agent's instructions. The agent opens the books by starting a helper program itself, so it can also read every file in the folder directly. That is how an agent ended up reading the journal file instead of asking the books.

After this plan. The books move into a private folder that belongs to a small books server. The server runs as you, only while the app, an agent session or a terminal is using it. Agents are never told where the folder is, and they only talk to the server. In practice:

• You install once, with at most three commands and no administrator password (on Linux, the package manager asks as it always does). After that you just type claude in any folder. There is no project folder, there are no helper commands, and there is nothing to do at the start of a session: starting the agent opens the books.
• Claude Code and Codex reach the same books the same way. Later, claude.ai on the web does too.
• When an agent connects, the books tell it the rules, your company's conventions, what needs attention and what to do next. Step-by-step procedures also come from the books: setting up, the month-end close, handing off to the CPA, and the audit.
• Receipts reach the agent as readable text and pictures of the pages, not as giant blobs of data. Files go in and out through short-lived links.
• Social Security numbers and other tax ID numbers are typed and viewed only on a private page that asks for your passphrase. The agent only ever sees the last four digits.
• Backups and a tamper check run on their own.
• The viewer works as it does today. It reads the books directly and never changes them. Within a second it jumps to whatever the agent shows you.
• Posting, closing and reconciling bring up no new permission pop-ups. The agent still shows you each entry before it posts.

How private is it? Hidden, not locked. An agent cannot stumble into the books. Because the server runs as you, though, an agent that deliberately went hunting could find them, and the books say this plainly wherever privacy is reported. If you ever want a hard wall, run the same server on another machine you own. This plan includes that recipe, and the same setup is how claude.ai on the web reaches your books.

Along the way, the 20 problems found in the 2026-10-16 audit get fixed, and a 21st found while capturing the goldens in P0. The finish line is a full re-audit of Wanderland, done only through the books' own tools, in which every receipt and every entry is checked and signed off.

---

2. Principles: invariants the code enforces

#	Invariant	Enforced by
I-1	The MCP is the only agent interface to the books. Locally this is advisory (owner decision 2026-10-16): the server runs as the human, and the books are hidden, not locked. Mechanical enforcement is the self-host deployment on another machine, where agents have no access to the data root.	A data root outside every project directory (3.4), mode 0700, created with an explicit set_permissions call (not the umask). No tool, instruction, handbook text or result names a filesystem path (I-2, I-12). The stdio data-dir transport is removed from every connect path (dev-stdio refuses any data dir inside the data root). books.start, wanderbooks doctor and the docs report isolation: "same_user (advisory)". Landlock and seccomp confine the server itself where available; they do not restrict the agent and are never described as if they did. Test agent_uid_cannot_read_tenant, run in CI against the two-user self-host deployment, not the desktop default.
I-2	No tool takes or returns a server filesystem path.	Schema lint no_path_params: the build fails on any parameter matching *path*, save_to or *_file. Landlock harness no_tool_touches_outside_tenant, run with fuzzed arguments. Static check: no std::fs in ledger-mcp/src/tools/** outside the ledger-store APIs.
I-3	The journal holds all books state. Settings, conventions, decisions, draft states, evidence links, annotations, extraction records and attestations are journaled. Reports are pure functions of the journal. wanderbooks.toml is import/export text only. The server never reads a toml file.	ledger-core::settings replay. Property test settings_replay_is_pure (Store, Snapshot and the view are identical). Test toml_round_trip_zero_events. The daemon binary contains no toml file-read code path.
I-4	Money is exact Decimal, every entry balances, and posted entries are permanent. Corrections are reversal drafts that need evidence.	Existing kernel, Kani and Lean. New Step.draftReversal and Step.discard, with preservation proofs.
I-5	Evidence gate. One function, ledger_core::evidence::requirement, decides whether an entry may post. Store, MCP and GUI all call it. Reversals are not exempt. Depreciation, amortization and closes are exempt by origin, and the exemption is sourced.	The gate lives in Store::post_entry. Test reversal_needs_evidence. Test gui_and_server_gate_agree.
I-6	A confirmed commit is bound to the server's most recent preview of that exact draft (stale or altered drafts are refused). It does not prove that a human saw the preview, and locally the key is readable by any process running as the human (advisory).	preview_token = HMAC-SHA256 over (entry id, canonical draft state, settings seq, evidence-link set, policy result), keyed with a server secret held in keys/. A post with a stale token is refused with guard stale_preview.
I-7	The agent never holds a full TIN or vault key material.	Vault records are sealed with HPKE to a public key whose sha256 is journaled. The private key exists only wrapped in keyslots held by the customer. Unwrap code is reachable only from human-page handlers and the GUI unlock path (module-privacy test). A pattern-based TIN scanner fails closed on every tool result. A canary TIN/key fuzz test covers responses, errors, logs and the access log.
I-8	The GUI never mutates and never uses the MCP. Locally it reads the data root directly, read-only, as today. It finds the root from the platform's well-known location or from wanderbooks gui <book>, never from a project directory or wanderbooks.toml. books.show reaches it through ops/show.jsonl in the book's own data root, never through the MCP. Remote books (self-host) are viewed through a read-only replica stream (P9).	ledger-gui/tests/read_only.rs. Tests gui_works_under_read_only_landlock and gui_finds_root_without_project_dir. Test replica_snapshot_equals_store_snapshot (P9). The GUI writes nothing under the data root and leaves no files under $HOME except eframe preferences.
I-9	Every access through the server is logged, and logging fails closed.	A hash-chained access.jsonl (own genesis). Property: exactly one record per tool call, upload, download, human action, remote replica connection and backup, refusals included. The local viewer's direct reads are not logged, because the GUI never writes; the docs say so.
I-10	Tamper evidence. Every mutating result carries head {seq, hash}. The head is handed off when a session goes quiet. The customer can clone the archive and run wanderbooks verify-archive --expect-head. Backup and access records stay out of the journal, so they never advance the head they report.	Test backup_does_not_advance_head. Test clone_verify_expect_head.
I-11	No loss of ease of use. Local setup is at most 3 commands on a clean machine, with no sudo, no system account and no container, beyond installing the app itself (D-24: on Linux the package manager asks for sudo as it does for every package; the dmg, the Windows installer and the AppImage ask for nothing). There is nothing to do per session, it works from any directory, the daily flow adds no client permission prompts (no requiresUserInteraction), and the viewer updates within 1 s of a post.	Acceptance criteria in P2 and P5. Tests setup_needs_no_root and annotations_complete. The agent-eval harness.
I-12	Guidance survives client truncation, and never names a path. Connect text is at most 1,400 characters, and its first 512 stand alone and name books.start. Tool descriptions are at most 700 characters. No tool text mentions just, wanderbooks.toml, ~/, git, GitHub PRs or any filesystem path, the data root included, and no result names one.	Tests instructions_budget, tool_text_lint and no_result_names_a_path.
I-13	Formal-methods bar. Kani harnesses cover kernel arithmetic. Every new ledger command is a Lean Step with a preservation proof. A failing proof is a finding. All tools are pinned in mise.toml. Clippy reports zero warnings. Every mutation survivor is killed or documented as equivalent.	just check and just prove pass in every phase.

2.1 Conflict resolutions (explicit)

Question	Proposals	Resolution
Process shape	A: single process. B: gateway plus per-book worker. C: daemon, with a gateway when hosted.	One ledger-mcp serve process (A), both locally and on a self-host machine. Locally it runs as the human, only while something the human started holds it open: the app, an agent session, or a terminal. Nothing is installed to run in the background (owner decisions D-21 and D-23, 2026-10-18). Every local program is a mode of the one wanderbooks executable (D-22). It has no OAuth authorization server and only a minimal human-page surface. The multi-tenant front/worker split (B) belongs to the hosted service, which this plan does not build (section 11).
Isolation, and when it lands	A: P5. B: P6. C: P3. All three assumed a service user.	Owner decision 2026-10-16: "you, hidden away." The desktop gets no service user, sudo, system account or container. P2 moves the books into a server-owned data root (0700, outside every project directory) whose path no text ever names. This isolation is advisory and is labelled that way. Mechanical enforcement is the self-host deployment on another machine (P9). From P2 on, CI proves it with agent_uid_cannot_read_tenant against a two-user deployment. P2 needs journaled settings first (P1), because the server never reads toml.
Settings import	A: server reads legacy toml (from_legacy:true). B/C: agent passes text.	import_settings {toml_text, config_json_text?} only. A legacy fallback (today's settings::Live) survives only in dev-stdio, until a book is adopted. books adopt refuses a journal with no settings.set unless --toml FILE is given. The human's CLI reads that file and passes the text.
Before import	C: writes blocked by a settings_not_imported guard.	Never block. Legacy books keep legacy_files mode in dev-stdio (P1). Daemon books always have journaled settings (enforced by adopt and create).
Preview/post	A: confirmed. C: split tools plus preview_token. B: seven read-only twins.	Keep confirmed, add preview_token. Add one read-only twin, books.preview_entry, for the high-frequency post path, so claude.ai doesn't prompt on every preview. Close, reconcile, dispose, run_* and purge keep confirmed plus the token. confirmed without a token is accepted for one release with a deprecation warning. This limits churn in mcp_stdio.rs, oracle_mcp.rs and spec_mcp.rs.
requiresUserInteraction	B: on every post.	Not used anywhere in this plan (owner decision 2026-10-16: no added friction). Post, reverse, close, reconcile, dispose, run_*, purge_tin, consolidate_duplicates and import_settings carry destructiveHint plus preview_token, and the client's normal permission rules apply. Full TINs leave the agent's path through human pages: TIN-bearing outputs from P2, and all TIN handling in P7.
Harness deny rules	C: P0 .claude/settings.json deny rules.	Rejected. That is plan A, which is dropped. P0 corrects only the sentence in the server text and the generated template that caused the cat (/home/swaits/Documents/Wanderland-Books/AGENTS.md:68-69, "the journal is the evidence — read it"). This is a content fix, not a guard.
Defect 12 rule	A: everything through financing_accounts is excluded.	Classified by instrument (C). Payment-card and third-party-network payments are excluded (1099-K) and listed. A member's personal cash or check through 2100 stays reportable. An unknown instrument is undetermined.
Odd cent (17)	A: fair ties. C: rotating tie-break.	Cumulative apportionment (B), extending kernel::apportion (kernel.rs:309), its existing Kani proofs, and Apportion.lean.
Cash flow (1)	A/C: per-entry heuristics.	Structural partition plus direct-method lines (B). Footing becomes an identity derived from trial-balance balance. A nonzero difference is an engine error.
Vault crypto	A: bespoke X25519/HKDF/XChaCha.	HPKE, RFC 9180 (X25519-HKDF-SHA256, ChaCha20-Poly1305) (B). The public key's sha256 is journaled. W-9 files are sealed into the vault and never become blobs.
Vault unwrap	A: model A first. C: client-side default.	Model A, locally and on self-host. The server unwraps inside one human request, or the local GUI unwraps in its own process after the human types the passphrase. Client-side unwrap (model B) is a requirement of the hosted service (section 11).
Human-session bootstrap	A: wanderbooks open-link, which a same-user-ID agent can mint.	Rejected. Every /h/ page needs a factor that requires human presence: a passkey with user verification, or the owner passphrase set at install. That passphrase becomes vault keyslot 1 in P7.
Replica keyring route	A: /replica/keyring serves wrapped keyslots to books:view.	Removed. No route ever serves wrapped keyslots. Local GUI TIN click: the GUI reads the wrapped keyslot from the data root (read-only), unwraps in its own process after the human types the passphrase, copies the value to the clipboard only, and zeroizes. A remote replica (P9) carries no keyslot material; remote TINs are seen only on /h/ pages.
TIN output scanner	A: match decrypted vault records.	Pattern-based (extend has_full_tin/redact_full_tins behind S:870 to every result, with the vault's last-four set as a hint). Fails closed. Documented as a pattern check.
Extraction	In-process (A/B).	Sandboxed subprocess ledger-extract (C): rlimits, seccomp, no network, Landlock read-only on the input blob.
Archive vs Landlock	A: server shells out to git, which contradicts its own Landlock rules.	A separate archive process, ledger-mcp archive, that the host starts beside the server, after the server holds every book's lock, and stops with it (3.9); each confines itself on its own. The archive process has read-only Landlock on books/<id>/{journal.jsonl,blobs}. Locally, Landlock ABI ≥ 4 limits its TCP connect to the target's port (443 or 22); it cannot filter by host, and an unprivileged process has no host-level egress filter, so that exists only under a system unit on self-host (IPAddressAllow). Locally the server listens on Unix sockets (3.9); if the owner turns TCP on, it binds 127.0.0.1 first. Either way Landlock ABI ≥ 4 then denies all further TCP bind and connect, so the local server has no egress. On self-host, a system unit adds IPAddressDeny=any (loopback allowed); if the built-in authorization server fetches CIMD documents (D-7 a), connect is allowed to port 443 only and IPAddressDeny narrows to private and link-local ranges (loopback still allowed), matching the CIMD SSRF guard. This confines the server only; it does not restrict the agent.
Attention engine location	A: ledger-store/attention.rs. B: wasm-clean ledger-view.	New crate ledger-view (depends only on ledger-core), holding attention::find, next_steps, the evidence gate view, and a BooksView trait implemented by Store and Snapshot. A pure-Rust evidence projection (dropping SQLite from the viewer) is deferred to the hosted service's web viewer (section 11).
Inline bytes	A: 256 KiB. B: 1 MiB without sha. C: 256 KiB plus sha.	256 KiB with a mandatory matching sha256. A mismatch is refused with guard base64_corrupt, whose remedy is books.begin_upload. /mcp body cap is 1 MiB.
Same-user mode	C: an announced tier. B: refuse to start without an acknowledgement flag.	The local default, with no gate flag (owner decision 2026-10-16). books.start, Needs attention, wanderbooks doctor and the docs report isolation: "same_user (advisory)".
Viewer channel	A: replica over a peer-credential socket.	Direct read-only disk access locally. This is the owner's rule: "the GUI has r/o access to ALL state on disk; it never mutates; it doesn't go through the MCP." books.show requests reach the GUI through ops/show.jsonl in the book's own data root, which the server writes and the GUI watches. Presence is a shared flock that the GUI holds on a read-only descriptor of ops/viewer.lock. Locally there is no socket, no peer-credential check and no executable check. The replica protocol exists only for viewing remote books (P9).
Local token	A: literal header in the Claude config.	OS keyring, read by the bridge (D-23): Claude Code and Codex run wanderbooks mcp --book X over stdio, and the bridge reads the token itself, so no client config holds it. headersHelper/http_headers_helper running wanderbooks token print remain for clients that choose HTTP.

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3. Architecture

3.1 Processes

From P2 every local program here is a mode of the one wanderbooks executable (D-22): ledger-mcp serve is its server mode, ledger-gui its viewer, ledger-extract its extractor, each run as its own process. The names below are the crates'. Claude Code and Codex reach a local book through the bridge, wanderbooks mcp (stdio, D-23), which speaks MCP to the server over a local socket (3.9).

                  agents (any directory, any client)                               human
   Claude Code (any dir)   Codex    claude.ai / ChatGPT    stdio-only       browser         ledger-gui
          |                  |      (P9: self-host or     (wanderbooks         |            (as the human)
          | wanderbooks mcp  | bridge  tunnel)            mcp --url)           | owner           |
          |  (stdio, lease)  |         | OAuth or token        |               | passphrase      |
          v                  v         v                       v               v                 |
   +---------------------------------------------------------------------------------+          |
   | ledger-mcp serve    local: open while held (D-23), as the human                 |          |
   |                     self-host (P9): same binary on another machine              |          |
   |   confines itself where available (Landlock, seccomp, no outbound TCP)          |          |
   |   /b/{book}/mcp   /b/{book}/u/{id} PUT   /b/{book}/d/{id} GET                   |          |
   |   /b/{book}/h/*  (human pages)    /b/{book}/replica/*  (P9, remote books only)  |          |
   +---------------------------------------------------------------------------------+          |
          | sole writer (0700; the path is never named)    ^ read-only Landlock                 | read-only,
          v                                                |                                    | direct
   <data root>/books/<id>/ journal.jsonl blobs/ ops/show.jsonl ... <-----------------------------+
          ^                                                |
          | sandboxed subprocess (rlimits, seccomp, no net) +-- ledger-mcp archive --------> git / s3 / dir / pull
   ledger-extract (pdf / xlsx / eml / page raster)

The data root is $XDG_DATA_HOME/wanderbooks on Linux (default ~/.local/share/wanderbooks) and ~/Library/Application Support/wanderbooks on macOS. It sits outside every project directory, and no tool, instruction, handbook section or result names it. Because the server runs as the human, this isolation is advisory: an agent cannot stumble into the books, but an agent that deliberately hunts for them could read them. The server's own Landlock and seccomp confinement limits what a compromised server can do; it protects nothing from the agent and is never described as if it did. Mechanical enforcement is the self-host deployment (3.8, P9).

Process	Binary	Runs as	Reads tenant disk
Books server (local)	the server mode of wanderbooks (the ledger-mcp crate), listening on run/mcp.sock (and on 127.0.0.1:7411 only if the owner turns TCP on), started by the first opener (the app, an agent's bridge, or wanderbooks serve) through the host mode, and running while any opener holds it (D-21, D-23, 3.9; the host reads no books: it starts the server and the archive process, each confining itself, and stops both). TCP is off by default (3.9)	the human	yes, sole writer, holds the flock (ledger-store/src/store.rs:74-89)
Books server (self-host, P9)	the same binary under a system unit on another machine	a dedicated account on that machine	yes, sole writer
Archive pusher	ledger-mcp archive --book <id>	the server's account, a separate process started beside the server	read-only journal and blobs
Extractor	ledger-extract (subprocess)	inherits, sandboxed	the single input blob, via fd
Viewer	wanderbooks gui <book>, the viewer mode (the ledger-gui crate; local, direct, the default; what opening the app shows); wanderbooks gui --books <url> (remote replica, P9)	the human	local: yes, read-only, never writes. Remote: none
CLI	wanderbooks (ledger-cli)	the human	by design never. Talks to run/admin.sock (peer-credential check: same user ID as the server). The admin socket cannot read books data; it can create or adopt books and mint agent tokens, admin-scope ones included. The peer-credential check keeps other local accounts out; any process running as the human, agents included, can use it (advisory, like the rest of the desktop deployment).
Agent bridge	wanderbooks mcp --book <id> (stdio to the agent; --url for a remote book, P9)	the agent's user	never; it has no data-dir flag. It may start the host (D-23), whose server then reads the disk as itself
Test/demo	ledger-mcp dev-stdio --data-dir	any	refuses inside the data root; wanderbooks connect never configures it (D-18)

3.2 Transport (one code path, local and remote)

Replaces StreamableHttpServerConfig::default() in serve_http (ledger-mcp/src/main.rs:154-180) with an explicit configuration:

• allowed_hosts taken from server.toml (deployment config only).
• enforce_origin_validation() with an explicit list: loopback by default, plus https://claude.ai once OAuth exists in P9. Today's empty list turns the Origin check off.
• json_response=true.
• legacy_session_mode=true while Cursor and claude.ai stay on ≤ 2025-11-25.
• max_request_body_bytes = 1 MiB.

Both protocol eras are served: initialize and server/discover are both built from get_info, which calls refresh first, with cacheScope: private and ttlMs: 60000. rmcp features gain elicitation and request-state (ledger-mcp/Cargo.toml:22). Tools read the principal through Extension<http::request::Parts>. Long calls (CPA package, audit, extraction backfill, consolidation) run under spawn_blocking and return {job_id} when they exceed 20 s; books.job polls. The 240 s claude.ai limit and Codex's 60 s are therefore never hit.

Concurrency. One Store per book behind tokio::sync::Mutex (replacing the std mutex at S:553). Tool bodies use blocking_lock inside spawn_blocking. Readers use a Snapshot refreshed after each write, so reports never wait on the writer.

3.3 Auth and scopes

Scope	Allows	Default holders
books:read	reads, reports, start, handbook, get_receipt text and images	all
books:write	drafts, lines, attach, annotate, upload, attest, settings preview	agent
books:post	confirmed post, close, reconcile, dispose, run_*, settings commit	agent (local default)
books:admin	tokens, access log, backup run, consolidate, invite	owner's agent (local default), owner
books:view	remote replica only (P9)	viewer client only, never agents

No scope unwraps the vault. Unwrap happens only inside an /h/ request that has just presented a human factor, or inside the local GUI process after the human types the passphrase (3.6).

• Local: a static bearer wb_ + 32 random bytes, stored only as a sha256, compared in constant time, kept in the OS keyring, minted by wanderbooks connect, and revocable with wanderbooks token revoke. Agent and server run as the same user, so the token identifies the client and keeps other local users and web pages out. It is not a wall against processes running as the human.

  • Claude Code: wanderbooks connect claude-code --book <book> (also the app's "Connect Claude Code") runs claude mcp add --scope user wanderbooks-<book> -- <absolute path of wanderbooks> mcp --book <book>: stdio, through the bridge (D-23). The bridge reads the token from the keyring itself, so Claude's config holds no token and no helper. It offers a permissions.allow mcp__wanderbooks-<book> line.

  • Codex: wanderbooks connect codex --book <book> writes:

    [mcp_servers.wanderbooks-acme]
    command = "<absolute path of wanderbooks>"
    args = ["mcp", "--book", "acme"]
    

    The bridge answers initialize within Codex's startup timeout, opening the books first if they are closed. A client that needs HTTP can be pointed at http://127.0.0.1:7411/b/<book>/mcp with wanderbooks token print as its header helper once the owner turns TCP on (3.9); it holds no lease and needs the books already open. No default_tools_approval_mode is written. Codex documents writes as prompting for every tool not marked read-only, which would prompt on every post, close and reconcile (against owner decision 3); leaving the key unset keeps Codex's normal rules.

• Self-host, remote (P9): the same static bearer over TLS for clients that send headers (Claude Code, Codex). claude.ai and ChatGPT need OAuth, so the self-hosted server offers OAuth 2.1 on this remote path only (D-7):
  • RFC 9728 PRM per book; 401 with resource_metadata.
  • 403 insufficient_scope for step-up.
  • RFC 8707 audience equal to the book URI.
  • PKCE S256, RFC 9207 iss, CIMD preferred (SSRF-guarded), DCR fallback.
  • Exact redirect match (https://claude.ai/api/mcp/auth_callback, loopback on any port).
  • offline_access only in the authorization server metadata.
  • 1 h access tokens with rotating refresh tokens.
  • Signing keys held through systemd-creds.
  • The self-hosted server is its own issuer (D-7 a), or it validates an external IdP's tokens (D-7 b). Codex uses codex mcp login.

Human factor for /h/: passkey with user verification (webauthn-rs; localhost is a secure context), or the owner passphrase (Argon2id, RFC 9106, m=64 MiB, t=3, p=1). Locally the passphrase is the default. Cookies are __Host- and SameSite=Strict, with CSRF tokens and CSP default-src 'self'. URL-mode elicitation is used where the client declares it, and the server requires that the session's sub equal the token's sub.

3.4 Data layout (server-owned data root, 0700)

<root>/                         Linux: $XDG_DATA_HOME/wanderbooks (default ~/.local/share/wanderbooks)
                                macOS: ~/Library/Application Support/wanderbooks
                                self-host (P9): /srv/wanderbooks
  server.toml                   deployment only: listen, public_url, allowed_hosts/origins, archive targets, issuer
  auth/principals.jsonl         principals, sha256(token), scopes, labels; passkeys (hash-chained)
  run/admin.sock
  legacy/<id>-<date>/           old copies moved here at adoption if the owner agrees (Q-3); the server never deletes them
  books/<id>/                   == today's data dir layout, unchanged (Store/Snapshot/verify_and_heal untouched)
    journal.jsonl  blobs/aa/bb/<sha>  wanderbooks.db(+wal/shm)  wanderbooks.lock
    vault/{tin,w9}-<party>.bin  HPKE-sealed (v2); moved from <books>/vault (S:511)
    keys/keyring.json           {pubkey, slots:[passphrase|recovery|passkey_prf|member_passkey]}, all wrapped
    keys/preview.key            HMAC key for preview_token (0600)
    keys/legacy.key             v1 raw key, P2..P7 only, deleted at rekey
    access.jsonl                hash-chained access log, own genesis "wanderbooks-access-v1"
    ops/backup.jsonl ops/heads.jsonl   not journaled
    ops/show.jsonl              books.show requests: the server appends (bounded, rotated), the GUI watches; not journaled
    ops/viewer.lock             created by the server; the GUI holds a shared flock on a read-only descriptor (presence)
    uploads/<id>.part           staging, swept after 15 min (a staged backup: kept until its restore ends, at most 24 h)
    derived/<sha>/page-N.png    disposable page-raster cache
    archive.git/                bare; journal.jsonl + blobs/ + vault ciphertext; age-encrypted on push; destination Q-1

The server, the CLI and the GUI resolve the data root with one shared function (ledger-store::paths::data_root(): the platform data directory, overridable with --root), never from the working directory, a project directory or a toml file. The root is created with an explicit set_permissions(0o700), not the umask. Extracted text is stored as a content-addressed blob, recorded in the journal by attachment.text_extracted, and archived with the books. Page rasters are disposable. Deleted assumptions: books_dir = data_dir.parent() (S:1155, ledger-gui/src/books.rs:1474, ledger-mcp/src/main.rs:102), the .gitignore check (S:531-543), and the $XDG_RUNTIME_DIR viewer file (ledger-store/src/viewer.rs:98-130), which ops/show.jsonl replaces.

3.5 Keys

Key	Location	Usable by
Vault public key	keyring.json; sha256 journaled (vault.created/vault.rotated)	server, to seal new TINs. A swap fails books.verify and verify-archive.
Vault private key	wrapped per keyslot; plaintext only inside one /h/ request (server) or one GUI unlock (in the GUI process, local), then zeroized	the human holding the passphrase, passkey PRF, recovery key, or an optional CPA keyslot
preview.key	keys/	server
Agent tokens	sha256 in auth/; plaintext in the user's keyring, which any process running as that user can read (advisory locally)	the agent's user
Archive credentials	OS keyring entry read by the archive process (local); systemd-creds for the archive unit (self-host)	archive pusher
At-rest encryption	full-disk encryption (desktop); encrypted volume (self-host recipe)	protects against stolen disks

3.6 GUI

• Local: direct and read-only (desktop default). This is the owner's rule: "the GUI has r/o access to ALL state on disk; it never mutates; it doesn't go through the MCP."
  • wanderbooks gui <book> runs ledger-gui --root <root> --book <id>. Without --root, the GUI resolves the platform data root itself (3.4). It never looks in a project directory or wanderbooks.toml.
  • It reads journal.jsonl and blobs into a Snapshot as today, tailing the journal so that a post appears within 1 s. Every open is read-only, and the GUI runs correctly with the data root under read-only Landlock (test).
  • books.show: the server appends {seq, ts, target} to ops/show.jsonl (bounded, rotated, not journaled). The GUI watches it with the same watcher it uses for the journal. This replaces viewer::request and the $XDG_RUNTIME_DIR viewer file (ledger-store/src/viewer.rs). A show request only navigates, so a stray writer can do no more than move the view.
  • Presence: the GUI holds a shared flock on ops/viewer.lock, opened read-only. The server probes the lock to report viewer.open and whether a show request was delivered.
  • Locally there is no socket, no peer-credential check and no executable check.
• Remote: replica (P9, self-host books only), ledger-gui --books <url> with the static token or OAuth, and books:view:
  • It pulls /replica/journal?after_seq=N (SSE of raw canonical lines) into Snapshot::from_lines(LineSource, BlobSource). This reuses the parse, chain-check and replay loop of snapshot.rs:137-183.
  • Blobs are fetched on demand, hash-verified, and kept in a 512 MiB in-memory LRU, never on disk. "Not fetched" is a separate state from "damaged" (fixes books.rs:456-478, attention.rs:551-568).
  • /replica/events carries books.show targets per principal, and presence.
  • The replica carries no keyslot material.
• Settings come from the journal. Deleted: data.rs:76-87,157-162,188-195, books.rs:536-542, main.rs:47-53, --books-toml.
• Needs attention comes from ledger_view::attention::find, so it is the same list as books.start.
• Save a copy / Open with system app on any document (Snapshot::attachment_bytes, snapshot.rs:328). Fixes the viewer half of defect 3.
• TIN click: locally, the GUI prompts for the passphrase, reads the wrapped keyslot and the sealed record from the data root, unwraps in its own process, and returns the value to the clipboard-only path (tests/tin_copy.rs behaviour), then zeroizes. This is not access-logged, because the GUI never writes; the docs say so. Remotely, TINs appear only on /h/ pages.
• [viewer] open_at_start becomes a per-human eframe preference (app.rs:833), not journaled.

3.7 Backup and tamper evidence

The archive process (ledger-mcp archive: locally started by the host after the server, and stopped with it, 3.9; a system unit on self-host) runs on a head-advance signal (debounced 30 s), on period.closed, on a timer while it runs, and once when it starts, for anything left unpushed. The books change only while they are open, so a backup is never missed while they are closed. "Back up now" in the viewer is the lease socket's back_up_now intent (3.9), opening the books first if they are closed. Each run:

1. Verifies the chain.
2. Commits the new journal lines and blobs to archive.git (one commit per push; the message is the seq range plus the head).
3. Pushes to the targets: git remote, S3, dir, or pull (the customer runs wanderbooks fetch).

It writes ops/backup.jsonl. books.backup {status|run} reports it, and Needs attention flags a target more than 24 h behind. Head handoff:

• every mutating result carries the head;
• ops/heads.jsonl records each 10-minute quiet period;
• the customer clones the archive and runs verify-archive --expect-head.

Email or webhook head delivery and a witness log belong to the hosted service (section 11).

Restore (owner, 2026-10-17: "these backups need to be restorable, both in existing and new installations"). A backup is complete: the journal, every blob, the vault records (sealed), and the head {seq, hash} at backup time. wanderbooks books restore <backup> [--id X] (and the viewer's "Restore…", which hands it to the server) works the same on a clean install and on an existing one. The server's Landlock keeps it inside the data root, so it never opens the backup by path: the CLI, or the viewer through its helper, stages the backup into the data root's uploads/ (re-hashed on arrival), and the restore intent carries only that staged id.

1. Proven before use. The server replays the whole chain, re-hashes every blob and checks that the head equals the one the backup records. Any mismatch refuses the restore with a plain reason; nothing is half-restored.
2. Never destructive. On an existing install a restore arrives as its own book beside the current ones. Replacing a book moves the old one into legacy/<id>-<date>/, kept, never deleted, and only on the owner's explicit choice.
3. The vault comes back only with its key. The backup carries the vault sealed; the passphrase or the printed recovery key (P7) unlocks it on any machine. Until P7 the v1 key is a separate file: a backup counts as complete only when that key is saved too, and Needs attention says so when it isn't.
4. Restore drills. On a schedule (default weekly, or at the next start if the books were closed when it fell due) and after each close, the archive process restores the latest backup into a scratch folder, verifies it as in step 1, compares its reports with the live book's as of the backup head, and throws it away. A failed drill is a Needs-attention item; books.backup status reports the last drill.

3.8 Local vs self-host

	Local (T1, the default)	Self-host (T2, P9)
Where	the human's computer	another machine the owner controls: home server, NAS or VPS
Processes	one server and its archive process, open while the app, an agent session or a terminal holds them (D-23)	the same binaries under system units, plus TLS (Caddy) and, optionally, wanderbooks tunnel
Runs as	the human	a dedicated account; agents have no account on that machine
Isolation	same_user (advisory): hidden, not locked	service_user (enforced): machine and user-ID boundary
Auth	static bearer in the keyring; /h/ uses the owner passphrase (or a passkey)	static bearer over TLS for header-capable clients; OAuth 2.1 for claude.ai and ChatGPT (D-7); /h/ uses a passkey or the passphrase
Vault unwrap	model A (server, inside the human request), plus the in-process GUI unlock	model A
Viewer	reads the data root directly, read-only	replica over books:view
Residual risk	a process running as the human (for example an agent that deliberately goes hunting) can read the data root, the agent token and the wrapped keyslots; TIN plaintext still needs the passphrase. The server's Landlock and seccomp confine only the server	whoever administers that machine

A multi-tenant hosted service is out of scope for this plan; see section 11.

---

3.9 How the books open and close (D-23)

The books are open while something holds them; there is no background service. This section is the mechanism; P2 builds it, P11 adds updates.

Who holds them. The app (the viewer), an agent session's bridge (wanderbooks mcp), a terminal running wanderbooks serve, and any CLI command that needs the server. Each holds a lease.

Three local channels, all in run/ under the data root (0700 on Linux and macOS; on Windows %LOCALAPPDATA%\wanderbooks, never the roaming profile, with an owner-only DACL; named pipes with an owner-only DACL, FILE_FLAG_FIRST_PIPE_INSTANCE, and a check of the client's SID):

• run/lease.sock: served by the host, leases only. Each lease records its kind (app, bridge, serve, cli) and PID; the app and wanderbooks doctor list them, so a stray holder keeping the books open can be seen and closed. Besides holding, the socket accepts exactly five owner intents, which is how the viewer hands work to the server: close, back_up_now, new_books, restore (a backup, as its own book beside the others), and consent_format_upgrade (a book). consent_format_upgrade, and a restore that replaces a book, carry the owner passphrase typed in the viewer, checked by the server (Argon2id, as on /h/); no MCP tool can give either, so an agent never consents. Nothing else is accepted.
• run/mcp.sock: served by the server, MCP for the bridge. Local agents never use TCP, so no other account on the machine can squat a port and catch the token or the traffic. Both ends check the peer's user ID (SO_PEERCRED/getpeereid, the pipe's SID). TCP is off by default. The owner can turn it on (server.toml, or wanderbooks serve --http) for a client that needs HTTP; it then binds 127.0.0.1:7411, a failed bind is reported by doctor and is not fatal, and such clients hold no lease, so the books must already be open.
• run/admin.sock: served by the server, admin only (create, adopt, tokens), as in 3.1. Neither the viewer nor the bridge opens it.

Starting the host cleanly. Every mode that confines itself (the viewer, the bridge) first starts a small unconfined helper (wanderbooks helper, spawned as its own process over an inherited socket pair before any thread, window or Cocoa start; never a fork of a running GUI), then confines itself. The helper accepts a fixed message set and nothing else: start_host; open_with an attachment id (the helper itself copies that blob, read-only, into a 0700 per-user directory, $XDG_RUNTIME_DIR/wanderbooks-open/ or its per-system equivalent, swept when the helper exits, and hands it to the system's default app; it never accepts a path or a command line); stage_backup, whose file the helper asks the owner for in its own file dialog (never a path from the viewer), copying it into the data root's uploads/ and returning a staged id for the restore intent; and start_updater, with no arguments. Only the helper starts the host, by a clean re-exec: environment scrubbed to a fixed allow-list (keeping XDG_RUNTIME_DIR and DBUS_SESSION_BUS_ADDRESS, which systemd-run --user needs, only after checking they point at the host's own user's runtime directory), stdin, stdout and stderr to null (a log file under run/), a new session (setsid), a fixed umask. On Linux under systemd (uwsm on Omarchy puts every app in its own scope, which would take the host down with the app) it re-execs through a transient systemd-run --user --scope, which installs nothing, persists nothing, and disappears with the host; elsewhere setsid alone. On Windows, CREATE_BREAKAWAY_FROM_JOB where the job allows it, and DETACHED_PROCESS. The host resolves the data root itself from the user's account (getpwuid home, or the known folder on Windows), never from the opener's environment, unless wanderbooks setup recorded another root. It refuses to run if it finds itself confined (seccomp in /proc/self/status, a Landlock write probe).

One host, even in a race. The host takes run/host.lock (an exclusive flock) before anything else; a second host exits and its opener attaches. The host starts the server, which takes every book's writer lock, and only then the archive process, so two archive pushers never meet on one archive.git. An opener that finds no live host and an unlocked host.lock starts one; one that finds a host shutting down (the lease socket refuses during shutdown) waits on host.lock, then starts a new one.

Closing. When the last lease ends, the host waits 10 s; a lease arriving in that time cancels the close. Then: no new requests, the one in progress finishes, every writer lock is released, the archive process finishes its push, and the host exits. "Close the books" (the app's menu, wanderbooks close) ends every lease at once; a bridge then tells its agent the owner closed the books and reopens them only in a new session. Before it ends leases the host says why on each one (closed_by_owner, restarting, idle_close). A holder that sees the connection end with no reason (a crash, a kill) starts a new host and re-takes its lease, with backoff (1, 2, 4 … 60 s, at most five tries); a host that keeps failing to start (a damaged journal, a panic) becomes a Needs-attention and doctor item, and a bridge answers its agent with a clear error instead of retrying forever. host_respawns and respawn_backs_off test it.

Restarting (an update, or the executable replaced by a package manager) is not a close. What lives between calls survives it: upload grants, download links, /h/ sessions and finished job results are kept in run/state/ (0600, the session key with them), and a running job delays the restart until it finishes. The host takes run/update.lock, closes the books as above but keeps the lease socket's holders informed, swaps (or, for a package-managed install, finds the new executable already in place), and restarts from the new executable. Openers that arrive meanwhile wait on update.lock. Bridges reconnect and re-initialize upstream without the agent noticing. A package-managed upgrade is noticed by the host (its executable's inode changed) and the restart happens the next time no request is in progress.

One version at a time. Children (server, archive, extractor) are started from the executable the host itself is running (/proc/self/exe or fexecve on Linux), never by path, so a swap mid-run can't mix versions. Where that isn't available (macOS, Windows) every child, bridge and lease handshake carries the version, and a mismatch triggers a restart. The lease, helper and bridge protocols carry protocol versions (not release versions, since a staged update can skip releases); each accepts its current version and the one before, and outside that range refuses with a plain message ("restart this agent session").

The bridge and slow starts. The bridge waits up to 5 s for the server and returns its real initialize (the connect text composed from the book, 4.1). If the server isn't ready by then (a cold start, a projection rebuild), it answers initialize itself, within a client's startup timeout (Codex allows about 10 s), from the tool list built into the same executable and a short generic text that points at books.start, which returns the book's rules. Calls are queued until the server is ready; a queued call fails after 60 s with a clear error that names wanderbooks doctor.

Format changes are the server's gate, not the updater's. A server that would write a newer journal format than a book has opens that book read-only, with guard format_upgrade_pending, until the owner consents in the app (or on a /h/ page). Before it asks, it makes a verified local backup that includes the keys (legacy.key until P7). Consent comes only from the owner (the passphrase, through the viewer's consent_format_upgrade or a /h/ page), never from an agent. Declining leaves the book as it was, and before consent the way back to a version that can write it is always there: a self-updating install keeps the previous verified app and offers "Go back to version X" (wanderbooks rollback); a package-managed one downgrades through its package manager (our apt and dnf repositories keep every release, and the AUR keeps old PKGBUILDs). This holds however the new version arrived: our updater, a package manager, or a hand install. After consent the previous version can no longer open that book, so "Go back to version X" refuses for it; the only way back is restoring the pre-upgrade backup, which would drop every entry since, so that restore says how many entries would be lost, arrives as its own book beside the current one (never replacing it), and needs the passphrase.

4. The MCP surface after the change

4.1 Connect instructions (composed in get_info; replaces INSTRUCTIONS S:57 and the string replace at S:8179)

Hard cap 1,400 characters. The first 512 contain books.start. Composed from journaled state:

wanderbooks: the double-entry books of {company.name|"a new company"}. Call books.start first in every session: it returns the rules in force, this company's conventions, what needs attention, and your next steps. These tools are the only way to the books; never look for them in local files. Amounts are decimal strings ("123.45"). Entries: books.draft_entry, books.add_line, books.preview_entry, show the human the preview, then books.post_entry with its preview_token. Posted entries never change; books.reverse_entry makes a reversal draft.
{evidence_rule}. No receipt yet? books.set_draft_state awaiting_evidence keeps the draft visible until it arrives. Files go in with books.begin_upload (inline base64 only under 256 KiB, with its sha256) and come out of books.get_receipt as text, page images or download links. Every change returns next_steps, guards and the journal head: follow them and show the human the affected balances. Never ask for, accept or repeat a full TIN: books.request_tin_entry gives the human a secure link. Procedures are prompts (onboard, month_end_close, cpa_handoff, audit); the guide is books.handbook or books://handbook.

{evidence_rule} comes from evidence::rule(&settings), which replaces ReceiptPolicy::rule() (ledger-config/src/receipt_policy.rs:147) and now names the required and exempt accounts. Wanderland example: "Every entry needs a receipt attached or linked before posting; depreciation, amortization and closes are exempt; a reversal needs its own receipt or the original's linked".

4.2 books.start (read-only, _meta["anthropic/alwaysLoad"]=true, ≤ 8 KB)

The v1 ships in P1 with the fields marked †. The full version ships in P5.

Input: {focus?: "daily"|"onboarding"|"close"|"audit", agent?: {model, reasoning_effort, harness}}. The agent block is self-reported and goes to the access log.

{ "book": {"id","name","url","timezone","today","fiscal_year":{"start","end"},"base_currency","basis"},   // †
  "you": {"principal","kind","scopes","client_id","verified":["principal","client_id"],"self_reported":["model","reasoning_effort"]},
  "isolation": "same_user (advisory)|service_user (enforced)",
  "head": {"seq","hash","last_handoff"},                                                                 // †
  "state": "needs_onboarding|active",                                                                    // †
  "rules": {"evidence","parties","capitalization","attestation_bar","approval_rules":"off"|[...]},       // † (evidence, parties)
  "settings_summary": [{"key","value","set_by","seq"}],                                                  // †
  "conventions": [{"id","kind","title","summary"}],                                                      // †
  "open_items": [{"id","title","due"}],
  "needs_attention": [{"id","severity","title","detail","tool","args","prompt"}],   // top 12 + counts by kind
  "drafts": {"building":n, "awaiting_evidence":[{"entry_id","date","amount","note"}], "reversal_drafts":[...]},
  "reconciliation": {"tracked":[...], "never_reconciled":[...], "behind":[...]},
  "attestation": {"bar":{...}, "due":[...], "attested_through"},
  "viewer": {"open":bool, "remote":[principal...], "how_to_open":"wanderbooks gui <book>"},         // remote: P9 replicas
  "backup": {"last_at","through_seq","stale":bool},
  "handbook_sections": [{"id","uri","chars"}], "prompts": [...],
  "next_steps": [{"tool"|"prompt","why","args","required"}] }

When state=needs_onboarding, next_steps = [{prompt:"onboard"}]. Conventions are presented as company policy data, not as directives, which keeps the server eligible for directory review.

4.3 Handbook

books.handbook {section?} (read-only) and books://handbook, books://handbook/{section}. The source is ledger-mcp/handbook/*.md, compiled in with include_str!. It is generic and carries no Wanderland leaks ("WL-0001" and "Due to Shareholders" become neutral examples).

Sections: contract, entries, drafts-and-reversals, evidence-and-receipts, attachments, files-in-out, reconciliation, fixed-assets, prepaid-and-recurring, revenue-and-payouts, parties-and-tins, 1099, closing, attestations-and-audit, cpa-handoff, settings-and-conventions, viewer, rules-that-change, control-roles, tracing-figures.

tracing-figures replaces "the journal is the evidence — read it" with "trace through books.get_entry, books.search_entries, books.journal_history". Each section ends with this company's conventions that apply to it, rendered from journaled convention.set events. The long tool descriptions move here: export_cpa_package (1,677 characters), set_entry_party (1,453), set_w9 (1,378), vendor_1099 (1,055).

4.4 Prompts (#[prompt_router]; the prompts capability is enabled at S:8172-8176; arguments are single tokens)

Prompt	Args	Drives
onboard	none	company facts → set_setting previews; chart template by entity type; members; timezone; evidence policy; attestation bar; opening entry; trial-balance check; offer migrate; offer to open the viewer
migrate	source=qbo|csv|sheet|other	import → compare_reference to the cent → record_decision cutover
process_inbox	none	each upload left on the human drop page → find or create the entry → attach → post when ready, or leave a draft awaiting evidence
receipts_from_email	none	attach_email flow
reconcile	account=CODE month=YYYY-MM	statement → record_statement → mark_cleared → reconcile
month_end_close	month=YYYY-MM	data-driven: tracked accounts, financing-account review, schedules, depreciation, recurring, close_step conventions, books.audit scope=month, close_period, month-end attest_period
cpa_handoff	year=YYYY	full audit at the bar → attestations → export_cpa_package (no TINs) → request_human_download
annual_compliance	year=YYYY	calendar by entity type, 1099 work, open items
audit	scope=month|annual|cpa_handoff|full	the adversarial procedure: separate verifier agents, per-receipt extraction against page images, attest_receipt, review_entry, attest_period

4.5 Resources (advertised templates; URIs repeated in structuredContent and in text)

Resource	Contents
books://start	—
books://handbook/{section}	—
books://conventions	—
books://settings	—
books://reports/{kind}{?start,end,as_of}	today these take no dates (S:8189)
books://digest{?since,as_of}	the bare form works; the default is since the last session head (fixes types.rs:1520)
books://entries/{id}	—
books://attachments/{id}	metadata plus extracted text
books://attachments/{id}/page/{n}	PNG
books://attachments/{id}/file	BlobResourceContents up to 1 MiB; larger files return an error naming get_receipt view=link
books://journal/{seq}	—
books://workpapers/{id}	—

books://receipts/{id} (S:8142, base64) remains for one release as an alias of /attachments/{id} with text.

4.6 Result envelope (single choke point in call_tool, S:8160)

{ ...payload,
  "next_steps": [{"tool","args","why","required":bool}],
  "guards":     [{"code","message","remedy_tool","remedy_args"}],
  "warnings":   [...],
  "head":       {"seq","hash"} }           // on every mutating result

next_steps::decorate(tool, &result, &view) takes items from ledger_view::attention filtered to the touched subject, plus tool-specific steps. Examples:

• After a post: attach or attest evidence if it is missing, books.show entry, the affected balances.
• After a reversal draft: add evidence.
• After a close: attest_period.
• After export_cpa_package: the human download link.

Report results also carry as_of_status {drafts_open_on_or_before, unreconciled, attested_through, settings_problems}. Properties: every mutating result has a head and a non-empty next_steps; every guard names a remedy tool that exists.

4.7 Files in and out

In:

• books.begin_upload {sha256, size, mime, file_name, purpose: receipt|document|import} returns {upload_id, put_url, curl, human_url, expires_at, max_bytes}. If the bytes are already stored it returns {existing_attachment_id}.
• PUT /b/{book}/u/{upload_id} is single-use, valid 15 minutes, bound to the principal, sha and size, capped at 25 MiB by default, and re-hashed before acceptance.
• human_url is a drop zone on /h/inbox for clients with no shell (claude.ai).
• attach_receipt, file_document, import_bank_csv, import_chart_csv and attach_email take upload_id | inbox_id | sha256 | content_base64 (≤256 KiB + required sha256).
• books.inbox / books.discard_inbox_item manage the drop zone.
• openai/fileParams is declared on the attach tools (P9). An MCP App upload widget comes in P9.

Out:

• books.get_receipt {id, view: meta+text (default) | text | page_image{page, max_px:1568} | link | bytes (≤256 KiB, with sha)}.
• books.download_link {attachment_id|export_id} returns {url, expires_at, sha256, size}. Links are single-use, valid 10 minutes, access-logged, and served with Content-Disposition: attachment and nosniff.
• export, asset_labels and export_cpa_package return a link, plus inline JSON/CSV when ≤ 50K characters.
• TIN-bearing outputs come only from books.request_human_download, which returns an /h/ link.

Typical receipt flow (Claude Code, the daily case in 7.2): sha256sum → books.begin_upload → curl -T the file to put_url → attach_receipt {upload_id} → get_receipt (text) → draft_from_template or draft_entry → preview_entry, shown to the human → on "yes", post_entry with the preview_token → next_steps and the head come back, and books.show moves the viewer to the entry. No step raises a client permission prompt beyond the client's normal rules. "Save it as a draft" is set_draft_state awaiting_evidence. On claude.ai, files ≤ 256 KiB go inline with their sha256; larger ones go through human_url and the process_inbox prompt.

4.8 Drafts waiting on evidence

• Draft states are building | awaiting_evidence{note}, plus reversal drafts.
• Open drafts appear in books.start.drafts, the digest, Needs attention ("Draft #52 awaiting receipt: Figma annual plan, noted 2026-10-16") and every report's as_of_status.
• A close is refused while a draft in the period is open (existing Lean hdrafts). discard_draft is the way out.
• export_cpa_package refuses while a draft dated on or before as_of is open, unless given allow_open_drafts {reason}.

4.9 Tool changes

New:

Area	Tools
session	books.start, books.handbook, books.job, books.journal_history {after_seq?, types?, subject?, limit} (the only way to "read the journal"), books.viewer_status
settings / conventions	books.settings (from the journal, with provenance and schema), books.set_setting, books.import_settings {toml_text, config_json_text?}, books.export_settings, books.conventions, books.set_convention, books.retire_convention, books.record_decision, books.decisions, books.open_items, books.raise_item, books.resolve_item, books.draft_from_template {template_id, ...}
drafts	books.preview_entry (read-only), books.list_drafts {as_of?, state?}, books.set_draft_state, books.discard_draft {reason}, books.inherit_evidence {entry_id, from_entry, reason}
chart	books.rename_account
evidence	books.begin_upload, books.inbox, books.discard_inbox_item, books.attach_email, books.find_attachment {sha256|md5|receipt_number|text}, books.annotate_attachment, books.consolidate_duplicates, books.add_instrument, books.instruments, books.set_entry_instrument, books.download_link
assurance	books.audit {through, scope} (job, deterministic workpaper), books.workpaper, books.attest_receipt, books.review_entry, books.attest_period, books.attestations
ops	books.backup {status|run}, books.access_log (admin), books.invite {kind: cpa|member|viewer, email} (admin; remote people need the self-host server, P9)
migration	books.compare_reference {reference_attachment, as_of, mapping_convention}, books.record_inventory {source, items|upload_id}, books.check_inventory {listing}
reports	export kinds members_equity, general_ledger, general_journal (JSON with entry_id)
vault (human links)	books.request_tin_entry {party, kind: ssn|ein|itin|w9}, books.request_human_download {what: cpa_package_with_tins|vendor_1099_with_tins|w9, party?, year?}, books.set_w9_facts {party, name, classification, address, signed_on, exempt_payee?}

Changed:

• post_entry requires preview_token; the gate moves into Store; the result carries posted_seq and posted_at.
• reverse_entry creates a reversal draft, with evidence: "link_original" | {attachment_ids} | "later".
• attach_receipt and file_document deduplicate by sha: identical bytes link the existing record, so "deduplicated" becomes true. Text is extracted at attach.
• get_receipt: views as in 4.7.
• digest (defect 6).
• Reports: one default range, as_of_status, and strict.
• cash_flow: reconciles, noncash_disclosures, operating_reconciliation.
• vendor_1099: instrument-aware; include_tins and save_csv_to dropped.
• set_vendor_1099 takes an explicit not_reportable plus a reason.
• register_asset: in_service_date + acquired_date, with purchase_date kept as an alias for one release; basis fields.
• list_assets: accumulated_posted and accumulated_scheduled_through.
• list_schedules: start, end, convention, next, remaining.
• parties: last four from party.tin_set.
• add_account: tax-category warning, or refusal under the policy.
• show: refuses start > end; appends the target to ops/show.jsonl in the book's data root (locally) or to the replica event channel (P9, remote viewers), and reports whether a viewer is open and was reached. The result never names a path.
• verify: also checks access.jsonl, the vault public-key sha and extraction blobs.
• export_cpa_package: no-TIN package returned as a link; becomes a job.

Annotations (P0): every tool gets a title and readOnlyHint or destructiveHint, plus idempotentHint where true. Corrections: export_cpa_package is no longer marked read-only; verify, list_periods, ar_aging and ap_aging are annotated. No tool gets requiresUserInteraction (2.1; owner decision 2026-10-16).

Removed:

• import_local_file (S:4511): restricted in P0, deleted in P2.
• get_w9.
• set_tin's tin and set_w9's tin/w9_file_path: guarded in P0, deleted in P7.
• Every save_to/save_csv_to (types.rs:368, 2563, 2686, 2758-2764): deleted in P2.
• include_tins.
• The INSTRUCTIONS const.
• viewer::request (replaced by ops/show.jsonl).
• --books-toml/--config in serve mode.
• Every mention of just or wanderbooks.toml in tool text: S:340, 390, 525, 546, 637, 640, 1902, 3061, 3251, 3374, 4060, 4315, 4568, 5194, 5829.
• server.rs (8,529 lines) is split into tools/<group>.rs as each phase touches a group.

The tool count goes from 93 to about 125. Only books.start and books.handbook load upfront under tool search.

---

5. State migration

5.1 Format gate (P0, before any new event)

• An unknown type is no longer JournalCorrupt (store.rs:4419-4423, :4640, Snapshot, GUI). It becomes StoreError::NewerJournal {seq, type, need}, shown as "update wanderbooks".
• A one-time journal.format_set {format: 2, features: [...]} is written before the first v2 event.
• Fixture journals from every phase are added to books_written_under_older_rules_still_open.
• There is one executable (D-22), so an update never mixes versions; the host starts its children from its own executable (3.9). wanderbooks update updates a self-updating install (dmg, Windows installer, AppImage) and refuses on a package-managed one, saying to use the package manager. The local GUI reads the journal directly, so it hits the same NewerJournal gate; the replica protocol (P9) carries a minimum version header.

5.2 New events (all additive; legacy events replay unchanged)

Every event may carry an additive actor {principal, client_id, kind}, which replay ignores.

Event	Phase	Replay target
settings.set {key, value, effective_from?, source{decided_by, decided_on, citation?, note?}} / settings.cleared	P1	ledger_core::Settings (Lean Step.setSetting: balances and drafts unchanged)
convention.set {id, kind: posting_template|approval_rule|policy|close_step|calendar|mapping|note, title, body_md, structured?, source, supersedes?} / convention.retired	P1	Conventions
decision.recorded {id, subject, decision_md, decided_by[party], decided_on, evidence_attachment?, supersedes?}	P1	Conventions
open_item.raised / open_item.resolved	P1	Conventions
account.renamed {code, name, previous, reason}	P3	chart
instrument.added {id, kind: bank|business_card|member_card|member_cash_or_check|platform, label, last4?, owner_party?, account?} / entry.instrument_set	P3	Ledger (1099)
asset.basis_set {asset, rule: purchase|carryover_723|personal_use_conversion, fmv_at_contribution?, contributor_adjusted_basis?, tax_basis_723, depreciable_basis, built_in_gain_704c, sec704c_method?} (legacy asset.tax_basis_set still replays)	P3	assets
schedule.registered + convention (absent = monthly_even)	P3	schedules
vendor.1099_set value not_reportable{reason}; legacy null replays as undetermined	P3	vendors
period.closed with close_to: MembersCumulative{since_seq} (old variants replay as before)	P3	periods
entry.draft_state_set {id, state, note} / entry.draft_discarded {id, reason}	P4	Ledger drafts (Step.discard; draftsOpen at Ledger.lean:133)
entry.reversal_drafted {id, reverses, date, description} (lines derived from the original)	P4	Step.draftReversal; posted later by an ordinary entry.posted
entry.evidence_inherited {entry_id, from_entry, attachment_ids, reason}	P4	evidence
entry.posted + actor, preview_digest	P4	ignored by replay
attachment.text_extracted {id, text_sha256, extractor, version, pages, status: ok|none|failed}	P6	evidence
attachment.rendered {id, from: eml, pdf_sha256, headers{message_id, from, to, date, subject}, source_sha256}	P6	evidence
attachment.annotated {id, fields{receipt_number?, payee?, amount?, date?, instrument?, category?, source?, reimbursable_to?}, note}	P6	evidence
entry.settles {entry_id, settles[]}	P6	derived reimbursed
inventory.recorded, reference.compared {reference_sha256, as_of, mapping, workpaper, differences}	P6	migration
vault.created / vault.rotated {pubkey_sha256, scheme:"hpke-x25519-chacha20poly1305-v2"}, vault.keyslot_added / vault.keyslot_removed {slot_id, kind, label}, vault.resealed {party, kind, old_hash, new_hash}	P7	evidence; vault_tin (S:1326-1378) accepts the newest hash
audit.run {id, through, scope, program_version, through_seq, tb_hash, findings, workpaper}	P8	assurance
receipt.attested, entry.reviewed, period.attested {..., method{model, reasoning_effort, adversarial, verifier_agents}, verified{principal, client_id}}. counts is derived against the bar in force at that seq; it is never stored.	P8	assurance

Not journaled: the access log, backup runs, head handoffs, viewer preferences, page rasters, and any key material or key path.

Projection (schema v12, schema.rs:8):

• entries gains created_seq, posted_seq, posted_at (= ts of the posting line), draft_state, posted_by.
• New tables: settings, conventions, decisions, open_items, instruments, annotations, extractions, attestations, audits.
• Core keeps a side map Ledger.entry_meta: id → {created_seq, posted_seq, posted_at}, filled during replay, so the Snapshot sees it.
• projection_rows/compare_projections include all of them.

5.3 Setting keys (typed registry ledger-core/src/settings.rs; validators moved from ledger-config/src/lib.rs:434-622)

Each key has a validator, a docstring (which becomes the books.settings schema) and a sensitivity class: public, identity (the full value appears only in reports and packages; books.start shows it masked), or never (cannot be set). TIN-shaped values are refused in every key except company.ein.

Area	Keys
company	company.name, .entity_type, .tax_classification, .tax_form, .fiscal_year_start, .timezone (drives today(), replacing chrono::Local at S:1943), .legal{formation_state, formed, state_entity_number, address, registered_agent, partnership_representative, irs_name_control, duns}, .ein (identity; D-5, decided), .cpa (party), .members (effective-dated [{party, share, capital_account, distribution_account, files_jointly_with}])
books	books.accounting_basis, .cash_accounts, .financing_accounts, .investing_accounts, .asset_tag_prefix, .close_into, .close_sweep, .schedule_convention
policy	policy.evidence{threshold, required_accounts, exempt_accounts} (replaces config.json receipt_policy), policy.parties, policy.capitalization{de_minimis, twelve_month_rule, sources}, policy.require_tax_category, policy.attestation_bar (default per D-9), policy.cpa_package_requires_audit: refuse|warn (default refuse, overridable per export with a reason; D-9), policy.audit_cadence, policy.approval_rules: off|enforce (default off: approval_rule conventions are recorded but never block a post)

base_currency stays in store.created. [books] data_dir, [vault] key_file and [viewer] are dropped on import with a note. Unknown keys are reported as problems instead of being silently ignored.

5.4 toml import/export

ledger-config shrinks to a codec:

• toml_to_events(&str, &Settings) -> Result<Vec<Event>, Problems> emits only the diff.
• settings_to_toml(&Settings, &Conventions) writes provenance as comments.

The WANDERBOOKS_TOML template (ledger-cli/src/main.rs:237-347) becomes the export format. ledger-cli/tests/init.rs:305,354 become round-trip properties: export then import yields zero events, and every example imports. The config_parse fuzz target is kept, and fuzz_settings_replay is added.

5.5 Migrating existing books (generic)

• wanderbooks books adopt <data-dir> --id X [--toml FILE] [--config-json FILE] runs as the human, with no sudo, through the admin socket. The server, which also runs as the human, does the copy:
  1. Takes the source flock, so it refuses while a stdio server holds it.
  2. Verifies the chain and records head H.
  3. Copies journal.jsonl and blobs/, re-hashes every blob, rebuilds the projection, and checks that the head equals H.
  4. Imports settings from the given texts (preview printed, confirmation at the TTY) unless the journal already has settings.set events.
  5. Moves vault/*.bin into books/X/vault/, and the v1 key into keys/legacy.key.
  6. Seeds archive.git from the source's git history, filtered to the journal and blob paths, and records the old repository's last commit hash. The push destination is the owner's answer to Q-1.
  7. If the owner agrees (Q-3), moves the source data dir, its vault and the project folder's git history into <root>/legacy/X-<date>/. Nothing is deleted. If the owner says no, the source stays where it is, read-only, and Needs attention lists it as an exposed old copy.
• ledger-cli init/new stop scaffolding and call books create.
• dev-stdio keeps legacy_files mode for unadopted data dirs for one minor release; books.start returns next_steps: adopt.
• Legacy semantics kept:
  • entry.reversed stays a posted reversal. During the re-audit the original's receipts are linked with inherit_evidence (D-12, decided); any not yet linked are reported as legacy_reversal_exempt.
  • Old close variants keep their rounding.
  • Old schedules stay monthly_even.
  • A null 1099 type replays as undetermined.
  • Duplicate attachment records stay until consolidated.

5.6 Wanderland (staged; reversible until Q-3)

When	Step	Acceptance
P0	Install new binaries (still stdio). Capture golden JSON of TB, P&L, BS, CF, members' equity, GL, journal, vendor_1099, parties, assets, schedules and digest, as of 2026-10-11, every month-end, FY-to-date and today, through the old binary over MCP. By decision (2026-10-16) the first company's goldens are kept privately in its own books dir, not in this public repo: export_cpa_package zips plus a canonical JSON form made by that dir's goldens/canon.py (which normalizes the text each export varies, such as its timestamp), with the comparison protocol in its README.	Goldens stored
P1	The agent reads /home/swaits/Documents/Wanderland-Books/wanderbooks.toml (and books-data/config.json only by asking Stephen to state its values, since it sits under books-data/) and calls import_settings. Expected diff: • the 15 [company] keys; EIN as identity • members 50/50 → 3000/3001 with files_jointly_with • accounting_basis=accrual, policy.evidence.threshold=0.00 (Stephen, 2026-10-12) • cash_accounts=["1000"], financing_accounts=["2100"]; the citation is corrected to ASC 230-10-45-14(b) • parties=require (2026-10-15), timezone=America/Denver (D-13, decided) • policy.approval_rules stays off Conventions are proposed in one batch preview from AGENTS.md:74-227: • 9 posting templates: joint contribution as two entries; expense from joint personal funds → 2100; expense from Bluevine; household reimbursement (Dr 2100 / Cr 1000) with a note that Stephen gives the go-ahead before money moves, recorded with its source and not an enforced gate; 50/50 distribution; revenue 4000; card 2050 expense and payment; cash entries dated by bank posting date • policies: numbering, one file per receipt (PDF preferred), email as PDF, capitalization (policy.capitalization plus decisions 2026-10-11 and 2026-10-16) • close_step: "ask Stephen whether a member paid anything personally" • calendar: Utah annual report around Oct 4, renewal fee to taxes & licenses • memory-only rules become conventions: post when ready; decisions to Stephen go one question at a time; TINs only in the vault Decisions: one file per receipt (10-11), threshold (10-12), cutover with Sheet frozen as of 10-11 and reference attachment 37 (10-14), renumber 6100→6050 and card at 2050 (10-14), TINs in vault (10-15); light governance, meaning no consent paperwork, spending limits, signed memos or amendments for the two-member LLC, with decisions recorded with their source (10-16); local isolation "you, hidden away", the viewer reading the disk directly, no added permission prompts, and self-host now with hosting later (10-16). Open items: • IRS name control "WALN" discrepancy; letter = attachment 70, mailing pending • deferred revenue to be raised with the CPA before the first subscription Per-entry notes: entries 4 and 5 dated Oct 7 to match the Sheet.	Every golden report and export is byte-identical before and after the import. GUI shows Wanderland correctly with wanderbooks.toml renamed away. No approval_rule convention is created, and every daily-flow post still succeeds without an approval
P2 (pre-cutover)	Run verify-sheet and drive-manifest verify a final time and file their outputs as workpaper documents. Recapture goldens.	Both pass
P2 cutover (about 10 min)	1. Ask Stephen the two open cutover questions (section 10.3: Q-1 backups, Q-3 old copies; Q-2 is answered), one at a time, in plain English. 2. Quit the agent sessions and the GUI. 3. wanderbooks setup, with no sudo: it creates the data root (0700) and asks for the owner passphrase. Nothing is installed to run in the background (D-21). 4. Nothing to start: each command below opens the books while it runs, and afterwards the app or Claude opens them (D-23). 5. wanderbooks books adopt /home/swaits/Documents/Wanderland-Books/books-data --id wanderland (archive target from Q-1; old copies moved per Q-3). 6. wanderbooks connect claude-code --book wanderland (removes the old stdio registration made by just mcp-add, adds the bridge's stdio registration, wanderbooks mcp --book wanderland). 7. wanderbooks connect codex --book wanderland. 8. wanderbooks gui wanderland. 9. Remove justfile, .claude/settings.json hook, .codex/hooks.json, scripts/ (archived under the data root's legacy/); AGENTS.md/CLAUDE.md become a 3-line pointer ("connect the wanderbooks MCP; call books.start"). 10. The company/ records are already filed (Q-2, D-20); the local copies stay until P6.	books.verify over MCP equals H. Goldens byte-equal. books.start works from Claude Code started in ~ and in /tmp/empty, and reports isolation: "same_user (advisory)". No connect text, tool text, handbook section or result in a recorded cutover session names the data root. No step asked for sudo. If Q-3 is "move": the project folder holds no journal, blobs, vault or git history containing them. Viewer updates within 1 s. With every holder closed the books close cleanly (books.verify ok with the same head at the next open), and a Claude Code session started with the books closed opens them by itself, with no reconnect. Rollback (nothing posted on the server): close the books (wanderbooks close), move legacy/wanderland-<date>/ back to the project folder (or use the untouched source if Q-3 was "no"), and re-register the P1 binary's stdio server as before cutover. Rollback (entries posted): wanderbooks books export-legacy wanderland writes a data dir with the same head check, then the same re-registration
P3	Defect fixes change reports (cash flow, 1099 sections, asset fields, digest). Each difference is hand-adjudicated in the P3 change log. 1099 classification and 704(c) fields are shown to the CPA.	Change log signed off
P4	list_drafts. Leftover drafts are discarded or set to awaiting_evidence.	Zero unexplained drafts
P6	• consolidate_duplicates resolves the 11 redundant records (preview first). • Extraction is backfilled for all 66 attachments. • Receipt numbers 1000–1029 are annotated from the "Receipt ID" in each description. Anomalies become annotations: 1009 unissued; 1011/1020 byte-identical pairs (merged); 43/45/47 have no ID. The next number is derived as 1030. • Instruments: Bluevine, joint Amex, member cards, Chase Ink 2050. • verify-sheet.py's ALIASES/RECLASSIFIED/RENUMBERED tables (scripts/verify-sheet.py:52, 69-108) become a mapping convention, then compare_reference runs against attachment 37 as of 2026-10-11. • drive-manifest.json text goes to record_inventory; the Drive connector listing goes to check_inventory.	compare_reference gives 0 differences. Inventory has 0 gaps. Drive deletion becomes possible (still Stephen's call)
P7	wanderbooks vault init --book wanderland (on the human page, behind the owner passphrase): generates the HPKE keypair; keyslots for passphrase, recovery key (printed) and optional passkey PRF; reseals every record; journals vault.created, vault.keyslot_added×N, vault.resealed. A TIN is checked in the viewer, then keys/legacy.key and ~/.config/wanderbooks/vault.key are shredded (Stephen confirms).	Last-four and kind match the journal. No vault key material remains on disk except the wrapped keyslots in the data root (no v1 key, no ~/.config/wanderbooks/vault.key)
P10	Re-audit (section 8).	—

---

6. Security and threat model

This section covers the local (T1) and self-host (T2) deployments. Threats specific to a multi-tenant hosted service (other tenants, a hostile operator, SSN compliance) are in section 11.

Adversaries and controls

Adversary	Goal	Controls
The agent (careless or prompt-injected; locally it runs as the human's user ID, the same as the server)	read or alter books outside the MCP; see TINs	I-2, I-7, I-12: no text ever names the data root, which sits outside every project directory. Every call is access-logged. Destructive hints are set. preview_token. Locally this is advisory: an agent that deliberately hunts can read the data root, just as the human can, and books.start, wanderbooks doctor and the docs say so. TIN plaintext stays sealed even then, because unwrap needs the passphrase. Enforcement is the self-host deployment, proven by agent_uid_cannot_read_tenant. Where a company turns on approval-rule conventions (off by default), they are asserted by the agent (approval{by_party}): a policy, not proof, which the access log records
Network attacker or browser	DNS rebinding, CSRF against localhost	Host allowlist; Origin enforced (403); bearer tokens only on /mcp; /h/ cookies __Host- and SameSite=Strict, with CSRF tokens; no tokens in query strings
Compromised OAuth client (self-host remote path, P9)	over-broad access	PKCE, exact redirect match, iss, CIMD SSRF guard (public IPs, 5 s, 64 KiB), consent per client per book, minimal base scopes with step-up, 1 h tokens with rotating refresh
History rewrite or fork (any deployment)	alter or fork the books unnoticed	head in every result, quiet-period handoffs, verify-archive --expect-head against an independent clone
Stolen disk or backup	read books	full-disk encryption on the desktop, an encrypted volume in the self-host recipe; archive encrypted with age to a customer recipient; the vault is always ciphertext
Untrusted files (PDF/XLSX/EML)	parser exploit inside the data-owning process	the ledger-extract subprocess sandbox; fuzz targets
A compromised server process	reach beyond the data root into the human's account	the server confines itself where available: Landlock (filesystem limited to the data root; on ABI ≥ 4, all TCP bind and connect denied once its own listening socket on 127.0.0.1 is bound), seccomp, rlimits; extraction runs in a further sandbox. This limits the server; it does not restrict the agent
Other processes running as the human, on the desktop	read the books; drive the viewer	no mechanical control locally (same user). A same-user process can alter anything the GUI reads (journal, blobs, keyslots). Journal tampering is detected by the hash chain and head handoff, not prevented; a vault public-key swap fails books.verify; a forged show request can only navigate. The GUI never writes. Stated as the advisory residual in books.start, doctor and the docs; the self-host deployment is the enforced option

Immediate hole (P0). import_local_file (S:4511) does an unrestricted std::fs::read, so it can file ~/.config/wanderbooks/vault.key (ledger-vault/src/lib.rs:216-222), and get_receipt then returns the key as base64. P0 changes this:

• An explicit --import-root allowlist (default: $XDG_DOWNLOAD_DIR only).
• Canonicalize, then refuse anything under the data dir, the books dir, the vault dir or the key directory, symlink escapes, and non-regular files.
• Test import_local_file_refuses_key_and_journal, plus a property over generated paths.
• No requiresUserInteraction is added (owner decision 2026-10-16). The interim TIN-bearing tools (get_w9, set_tin, set_w9 with tin, vendor_1099 include_tins, export_cpa_package with TINs) keep today's behaviour (S:1198-1266, S:6111-6117).
• P2 deletes the path parameters and makes TIN-bearing outputs human-only. P7 deletes full TINs from the MCP entirely.

Access log record:

{seq, ts, prev, principal{id, kind: agent|human|viewer|cpa|system, label},
 client{client_id (verified), name, version (asserted)}, model? (asserted), request_id,
 action: tool|upload|download|replica.connect|human.tin_entered|human.tin_viewed|
         human.vault_unlocked|human.cpa_package|token.created|backup.run|keyslot.changed,
 subject, args_digest (sha256 of canonical args), result: ok|refused(code), head_after?}

Each record is fsynced, and a failed write fails the request. Readable through books.access_log (admin) and the viewer's Access page. The CPA package carries a summary. Its head is part of the head handoff. replica.connect occurs only for remote viewers (P9). The local viewer's direct reads, including its in-process TIN unlock, are not logged, because the GUI never writes.

Security test suite (ledger-mcp/tests/security_*.rs):

• auth on every route; wrong audience → 401; bad Origin → 403; bad Host → 400; body over limit → 413
• expired or replayed grant → 410; upload sha mismatch refused
• scope_step_up_403; handles_bound_to_sub; tin_entry_requires_same_sub
• unwrap_only_in_human_handler (module privacy plus grep gate; the GUI unlock path is the one other caller)
• vault_pubkey_swap_detected_by_verify
• no_mcp_output_contains_full_tin: canary TIN and key; session fuzz across responses, errors, server logs and access-log records
• no_result_names_a_path: the same session fuzz with the data root as the canary, across connect text, tool text, handbook, prompts, results and errors
• access_log_one_record_per_call, refusals included
• isolation_label_is_advisory: a local install reports same_user (advisory) in books.start and doctor
• agent_uid_cannot_read_tenant, run against the two-user self-host deployment in CI (the desktop default is advisory and is not claimed to pass it); no_tool_touches_outside_tenant (Landlock harness)

New fuzz targets: fuzz_http_mcp_request, fuzz_upload_put, fuzz_settings_replay, fuzz_extract_pdf, fuzz_extract_xlsx, fuzz_eml, and fuzz_replica_stream (P9). New mutation recipes and scheduled CI for ledger-vault, ledger-cli, ledger-view, and ledger-mcp/http; none of these have a recipe today.

Retention: 7 years. A local or self-hosted book keeps SSNs, sealed, on a machine the owner controls.

---

7. User flows

What you will see and do. The technical details are in sections 3 and 4.

7.1 Setting up on your computer

1. You install Wanderbooks the usual way for your system: a .dmg on a Mac, an installer on Windows, your package manager on Linux (D-24). No developer tools, and no administrator password (on Linux your package manager asks for yours, as it does for everything). On first open it:
   • sets up the books server. It installs nothing that runs in the background, and it does not ask for an administrator password;
   • asks you to choose a passphrase. You need it to type or see someone's Social Security or tax ID number, to download anything that contains them (such as the CPA package with them), and whenever the books open a private page for you, such as the page where you drop a big file;
   • creates your company's books;
   • connects Claude Code to the books, and Codex too if you have it;
   • tells you how the books open: opening Wanderbooks, or starting an agent, opens them; when the last of those closes, so do the books. Nothing runs in the background.
2. You type claude in any folder and say "set up my books". The agent sees that the books are new and walks you through setup: company facts, accounts, members, opening balances, and a check that everything balances. Every answer is recorded in the books.

7.2 Day to day

• You say: "The receipt is in Downloads, inv-883.pdf, the Figma annual plan." The agent sends the file to the books, reads it, drafts the entry, and shows you exactly what it will post. You say yes, it posts, and the viewer jumps to the new entry. Posting brings up no extra permission pop-up.
• You say: "Save it as a draft, I'll find the receipt." The draft stays on the to-do list until the receipt arrives. You see it in the viewer's Needs attention, and the agent sees it at the start of every session.
• You say: "Show me Q3 against last year." The viewer opens that report.
• Backups happen on their own while the books are open. Every change the agent makes comes back with a fingerprint of the books, so any tampering would show.

Compared with today: no helper commands, no project folder, it works from any folder, you answer the same number of questions, and installing needs no administrator password (on Linux, the package manager asks as it always does).

7.3 How private your books are

• The books live in a private folder that only your account can open, outside every project folder. Nothing the agent is told or shown names that folder, so an agent cannot wander in by accident.
• It is a curtain, not a lock. The server runs as you, so an agent that deliberately went looking could find the folder. The books say so whenever they report on privacy ("same user, advisory"), and wanderbooks doctor shows it too.
• Social Security and tax ID numbers stay sealed even then. Opening one needs your passphrase.
• For a real lock, run the books on another machine you own (7.4). The agent then has no way to reach the files at all.

7.4 Your own server, and claude.ai on the web

• You install the same programs on a home server, a network drive (NAS) or a rented server by following the recipe. Two commands move your books there, one on each machine, and the books' fingerprint must match before and after the move.
• One command gives that server a web address claude.ai can reach. Anyone can find the address, but only you can sign in. In claude.ai you go to Settings → Connectors → Add custom connector, paste the address and sign in.
• Then you chat as usual, for example "what needs attention?"
• Small receipt files go straight through the chat. For bigger ones, you drop them on a private upload page and say "process my inbox".
• Downloads come as one-time links.
• When someone's tax ID number is needed, the agent gives you a link to a private page and you type the number there. The chat only ever sees "last four 1234 recorded".
• The viewer on your computer can show the books on that server too. It streams a copy that it cannot change.

7.5 Codex

The installer offers to connect Codex, or you can run wanderbooks connect codex --book <name> later. After that you run codex from any folder. Codex gets the same rules and procedures as Claude Code.

7.6 Your CPA

1. On your computer, you send the CPA the package the agent prepares. With your own server (7.4), you can also invite the CPA to look at the books directly. The CPA signs in with their phone or computer's built-in sign-in (a passkey), with no password, and sees the reports, documents, journal and audit papers, all read-only.
2. The CPA package without tax ID numbers is an ordinary download.
3. The version with tax ID numbers comes only through a one-time link. You open it, unlock it with your passphrase, and send it on. Every download is recorded.
4. If the CPA wants, they can connect their own agent with read-only access.

7.7 What stays easy (acceptance)

• At most three commands from a new computer to the first posted entry, with no administrator password beyond the Linux package manager's usual one.
• Nothing to do at the start of a session.
• Everything works from any folder.
• The viewer catches up within a second.
• No new permission pop-ups in daily work.
• wanderbooks doctor shows on one screen: the server, your books, the connected apps, the viewer, the last backup, the books' fingerprint, and how private the books are.
• A test proves that an agent that knows nothing about the books can finish the everyday jobs just by following what the books tell it to do next.

---

8. Phased milestones

Every phase is one merge train. Each one:

• passes just check (fmt, clippy -D warnings, rustdoc -D warnings, all tests) and just prove (Kani with no vacuous covers; Lean with standard axioms only, no sorry);
• updates docs/parity.md, docs/spec/rules.md (SOURCE / CONVENTION / DECISION lines), docs/mcp-interface.md, docs/testing.md, docs/verification.md and docs/architecture.md;
• runs mutation testing on the crates it touches, with every survivor killed or documented as equivalent;
• builds features whole: core, store, MCP, viewer, exports, docs, tests.

Wanderland keeps working between phases.

P0: Guard rails (days)

Scope:

• import_local_file allowlist (defect 19, interim).
• NewerJournal and journal.format_set reader support.
• title plus a read-only or destructive hint on all 93 tools, with the corrections in 4.9. No requiresUserInteraction on any tool (owner decision 2026-10-16: zero added friction; TIN handling moves to human pages in P2 and P7).
• get_info calls refresh().
• Bare books://digest works.
• INSTRUCTIONS is replaced by an interim connect text (≤ 1,400 characters) plus books.handbook and handbook resources holding the scrubbed old text by section.
• tokio::sync::Mutex plus spawn_blocking (S:553).
• Pin cargo-mutants and cargo-fuzz in mise.toml:21-22.
• Remove the duplicate Transports section (docs/mcp-interface.md:78/:728) and the bearer-token claim.
• Template text fix ("trace through tools").
• Capture Wanderland goldens (5.6).

Tests: import_local_file_refuses_key_and_journal (property); annotations_complete (every tool has a title and a hint, and none carries requiresUserInteraction); instructions_budget; tool_text_lint; digest_resource_bare_reads; old_reader_gets_newer_journal.

Accept:

• A live Claude Code session receives the connect text untruncated.
• Wanderland's daily flow is unchanged, with no new permission prompts.

P1: Journal-native settings and conventions (B, part 1)

Scope:

• ledger-core/src/settings.rs and conventions.rs.
• Events settings.*, convention.*, decision.recorded, open_item.*.
• Ledger fold, so Snapshot and Store share Settings.
• ledger-config becomes the codec.
• Tools: settings, set_setting, import_settings, export_settings, conventions, decisions, open items, draft_from_template.
• Approval-rule conventions: supported by the engine for companies that want them, off by default (policy.approval_rules = off). They are enforced at post only after a company turns them on. The Wanderland import creates none (owner decision 2026-10-16: light governance; decisions are recorded with their source instead).
• books.start v1.
• company.timezone drives today().
• New crate ledger-view: attention::find moved from ledger-gui/src/attention.rs:68-571 together with its helpers (books.rs:643-650 missing_receipt, depreciation_due, w9_status, reconciliation_due, party_infos), over a BooksView trait.
• GUI reads settings from the Snapshot; journal-page describe arms (pages/journal.rs:825); Company page shows provenance; copy fixes company.rs:59, cash.rs:51, attention.rs:562; the "due to" heuristic uses financing_accounts (attention.rs:349).
• dev-stdio keeps legacy_files mode.
• Wanderland P1 steps.

Defects: none directly. P1 enables 8 and 16.

Proofs and tests:

• Lean Step.setSetting preservation (balances and draftsOpen unchanged).
• settings_replay_is_pure (2,000 cases, Store = Snapshot = view).
• toml_round_trip_zero_events.
• fuzz_settings_replay.
• attention_server_equals_gui (golden on fixture_company).
• Sensitivity: a TIN-shaped value is refused outside company.ein.
• approval_rules_off_by_default: with an approval_rule convention present and the default policy, a post succeeds without an approval; with enforce, it is refused until one is given.

Accept:

• Wanderland goldens are byte-identical before and after the import.
• The GUI is correct with the toml renamed away.
• books.start v1 is at most 8 KB.

As built (2026-10-17), and where it departs from the scope above (engineering calls):

• One event per change set: settings.set {changes: [{key, value|null}], source} is all or nothing (an import is one line); there is no separate settings.cleared (a null value clears). effective_from is not built: no key needs it yet, and effective-dated members are the varying-interest rule (§706(d)), which changes figures and belongs with the P3 allocation work. A later format adds it.
• Keys are flat (company.formation_state, company.irs_name_control, ...), not one company.legal{} object: each fact gets its own source, which is what "facts carry their source" asks. company.members keeps member names (matched to parties as before); company.cpa is text. policy.capitalization, require_tax_category, attestation_bar, cpa_package_requires_audit, audit_cadence and books.schedule_convention arrive with the phases that use them (P3, P8).
• ledger-view (attention::find moved out of the viewer) moves to P5, where its first user (books.start's needs_attention, next_steps) lands; P1 has no server-side consumer, and moving 700 lines of the viewer for nothing would be risk without use. attention_server_equals_gui goes with it.
• The "due to" heuristic keeps reading account names: financing_accounts also holds bank loans, which aren't "paid personally".
• Approval rules are checked by the engine (Ledger::approvals_missing) and enforced by the store: Store::post_entry refuses a covered draft until approved, and the operations that post at once (invoices, bills, payments, payroll, remittances, disposals) are refused when a rule covers the entry they would post (approval_gate: draft it instead). Reversals, closes, depreciation and amortization are exempt. An approval records the draft's fingerprint (date, description, lines, classes); any change voids it. A rule names accounts that take postings, and an account a rule names can't be renumbered until the rule is revised.
• books.import_settings takes only the file the server reads, whole (compared key by key with the server's own reading), never turns approval rules on, and on books that keep their own settings changes nothing (review round 1: an agent-transcribed text could drop the EIN).
• books.start v1 leaves book.id, book.url, head.last_handoff, the agent input and alwaysLoad for P5 (they need the served book identity and tool search).
• Posting templates take slots ({expense}): an account each draft names, so "an expense a member paid: Dr / Cr 2100" is one template.
• A vault key file is never a books setting: --vault-key-file on the server and the viewer, and an import is refused unless the key in force stays the same.
• The connect text's lead names books.start first, then the handbook.

P2: One executable, open while held, hidden away, and the Wanderland cutover

Scope:

• ledger-mcp serve --root with multiple books at /b/{book}/mcp; explicit transport config (3.2); bearer tokens and scopes; rate limits (tower-governor).
• One executable (D-22). wanderbooks is the only program: a thin dispatcher over the existing crates whose modes are the viewer (gui), the books server, the host, the agent bridge (mcp), the archive process, the extractor, and the CLI commands. Each mode that runs as a process confines itself at start, after forking its unconfined helper (3.9) and before it opens anything. The viewer, on Linux, confines itself read-only on the data root, with writes allowed only to its preferences folder and the Downloads folder (exports, Save a copy); Open-with and the updater go through its helper. A gui cargo feature, off in the self-host server build (P9), leaves the window libraries out. P11 then only packages it.
• Open while held, no service, no sudo (D-21, D-23). wanderbooks setup creates the data root (3.4) with an explicit set_permissions(0o700) (an owner-only DACL on Windows) and sets the owner passphrase. The books open when something holds them and close when nothing does, as section 3.9 describes: leases on the host's run/lease.sock, the helper's clean start of the host, host.lock, the 10 s close, "close the books", restarts, one version at a time, the bridge's own initialize, and the server's format_upgrade_pending gate. Nothing is installed or persistent: no systemd unit file, no LaunchAgent, no socket activation, no login autostart (the transient scope of 3.9 disappears with the host), and nothing runs after the last holder closes. There is no system account, no container and no root step.
• Honest isolation label. books.start, Needs attention, wanderbooks doctor and the docs report isolation: "same_user (advisory)". There is no --same-user flag and no acknowledgement gate.
• Self-confinement. Where available: on the server, Landlock (filesystem limited to the data root; on ABI ≥ 4, all TCP bind and connect denied once it has bound its own listening socket on 127.0.0.1) and seccomp; on the archive process, read-only Landlock on the journal and blobs, TCP connect limited to the target's port (443 or 22) on ABI ≥ 4, and seccomp. An unprivileged process cannot filter egress by host. If they cannot be applied, doctor reports it; it is not fatal. The docs describe them as protecting the human's account from a compromised server, not the books from the agent.
• Access log plus books.access_log.
• Owner passphrase for /h/ (Argon2id).
• Files transport: begin_upload, the PUT route, the /h/inbox drop page plus books.inbox and the process_inbox prompt, download_link.
• Every server-path parameter deleted: import_local_file, save_to, save_csv_to, w9_file_path, get_w9 save_to. W-9 upload moves to /h/w9/{party} (sealed with the v1 key until P7). TIN-bearing outputs come only through request_human_download → /h/, behind the owner passphrase. This closes defect 19.
• get_receipt view=link|bytes(≤256 KiB+sha) (defect 3, transport part).
• Viewer, direct and read-only (3.6): data-root discovery through ledger-store::paths::data_root() or --root from wanderbooks gui <book>, never a project directory or wanderbooks.toml; books.show through ops/show.jsonl (delete ledger-store/src/viewer.rs); presence through the ops/viewer.lock shared flock; Save-a-copy and Open-with (defect 3, viewer part). Locally there is no replica; the viewer's only channels are the lease socket's owner intents and its helper (3.9).
• Archive process and module; books.backup; ops/heads.jsonl; verify-archive; fetch.
• Restore (3.7, D-19): books restore, proven before use, never destructive, onto a new or an existing install; restore drills; the vault key's backup reported until P7.
• Viewer menu (D-19): "Export for CPA" (done by the viewer, into Downloads); "Back up now", "Restore…", "New books…", "Close the books" and format-upgrade consent handed over as the lease socket's owner intents (3.9); "Connect Claude Code" and "Connect Codex". Nothing in the viewer writes a book.
• wanderbooks mcp, the agent bridge (D-23, 3.9): stdio to the agent, MCP over run/mcp.sock to the local server (or HTTPS with --url, P9), the token from the keyring. It opens the books if they are closed and holds a lease for the session. Across a server restart (an update) it reconnects and re-initializes upstream without the agent noticing, sending notifications/tools/list_changed only if the tool list changed.
• CLI subcommands and modes: setup, serve, close, mcp, host, helper, rollback, books create|adopt|list|export-legacy, connect, token, gui, doctor, verify-archive, fetch, update. books export-legacy <id> (rollback only) writes a P1-format data dir outside the data root, verifies its head equals the server's, and stops the server's writes to that book.
• Scaffold deleted: JUSTFILE, AGENTS_MD, CLAUDE_SETTINGS, CODEX_HOOKS, GITIGNORE (ledger-cli/src/main.rs:43-521); install.sh rewritten, with no sudo.
• The test harness drives HTTP (mcp_stdio.rs keeps the bridge).
• Two-user CI deployment: a container that runs the server as a dedicated user and the agent as another, in the configuration P9 turns into the self-host recipe. It is the target of agent_uid_cannot_read_tenant.
• Wanderland cutover, preceded by the two open cutover questions (10.3).

Defects: 19 (closed), 3 (partial).

Tests:

• agent_uid_cannot_read_tenant (the two-user CI deployment; not the desktop default).
• setup_needs_no_root (setup, serve, adopt, connect and gui as an unprivileged user in a clean container; nothing is left installed to run in the background).
• books_close_cleanly (the last lease ending, "close the books", SIGTERM and SIGHUP of the host, all during a burst of posts: every request either completes or is refused, the head verifies at the next open, the lock is released); openers_share_one_server (the app, serve, a CLI command and two bridges started together: one host, one writer); books_close_with_last_holder (each kind of holder ending, kill -9 included: closed 10 s after the last, not before); bridge_opens_closed_books and bridge_survives_server_restart (the agent's session carries on, no reconnect); close_now_ends_every_lease; host_starts_clean (started from a confined viewer or bridge with a hostile environment, XDG_DATA_HOME and LD_PRELOAD included, the host is unconfined, finds the real root, and holds no inherited descriptor); host_respawns (kill the host: a holder starts a new one); host_survives_app_scope (under a systemd app scope, as uwsm sets up, closing the app that started the host leaves it running for the other holders); no_local_agent_tcp (the bridge never connects to TCP; TCP is off by default; with it on, a squatter on 7411 makes doctor report a failed bind and sees no bridge traffic); lease_socket_accepts_only_owner_intents (exactly the five; consent and replace without the passphrase refused); restart_is_not_close (bridges carry on across a restart; openers wait on update.lock); children_match_host_version (replace the executable mid-run: no child of the new version joins the old host); format_upgrade_waits_for_consent (read-only until the owner's consent, a backup with the keys made first, no MCP tool can consent, declining leaves the book openable after wanderbooks rollback); no_rollback_after_consent ("Go back" refuses for an upgraded book; the pre-upgrade restore arrives beside it, states the entries it lacks, and needs the passphrase); restore_reads_only_staged_backups (a restore intent naming a path is refused); bridge_initializes_during_cold_start; archive_catches_up_at_start (a push that failed before a close is made at the next open).
• one_executable (every mode from one binary; the viewer mode under read-only Landlock opens and follows a book); server_build_has_no_gui (the self-host build links no window libraries).
• viewer_without_server (with the server stopped or failing to start, the viewer still opens and follows the books from disk; "Restore…" and "New books…" say why they can't run).
• isolation_label_is_advisory.
• no_path_params schema lint; no_result_names_a_path.
• no_tool_touches_outside_tenant.
• security_* (auth, Origin, Host, body limit, grants, upload sha).
• access_log_one_record_per_call.
• gui_works_under_read_only_landlock; gui_finds_root_without_project_dir (started in an empty directory with no toml); show_request_reaches_gui (≤ 1 s); viewer_presence_reported.
• clone_verify_expect_head; backup_does_not_advance_head.
• restore_on_clean_install and restore_beside_existing_books (same head, identical goldens); restore_refuses_damaged_backup (a flipped byte in the journal, a missing blob, a head that doesn't match: each refused, nothing written); restore_never_overwrites (replace moves the old book to legacy/); restore_drill_failure_is_flagged; restored_vault_needs_its_key.
• viewer_menu_never_writes_a_book (backup and export leave the data root byte-identical; restore and new books go through the server).
• http_concurrency extended to 3 books × 6 clients while the GUI reads.
• upload_round_trip_byte_exact (20 MiB).
• GUI read_only: no writes under the data root, and no files under $HOME except eframe preferences.
• fuzz_http_mcp_request, fuzz_upload_put.

Accept:

• The 5.6 P2 checks.
• A clean machine reaches the first post in at most 3 commands, and no step asks for sudo.
• Claude Code from ~, and Codex, each recorded under its own principal.
• A Codex post, close and reconcile raise no approval prompt beyond Codex's defaults (no default_tools_approval_mode in the generated config).
• Two concurrent agents post 12 entries each with no lost writes.
• Viewer updates within 1 s.
• A backup of Wanderland restores on a clean machine and beside the live books, each with the same head and byte-identical goldens.

P3: Engine correctness (defects 1, 7, 21, 8, 9, 11, 12, 13, 14, 15, 16, 17, 18, 22)

Defect 1, cash flow (ledger-core/src/reports.rs:1231-1560):

• Partition. Every non-cash balance-sheet account belongs to exactly one section: investing (fixed-asset cost and accumulated depreciation, plus investing_accounts), financing (equity, plus financing_accounts), or operating (all others, including P&L).
• Scope of the body. Only entries that touch a cash account. Entries with no cash line go to noncash_disclosures (ASC 230-10-50-3/4), for example a member's property contribution (Dr equipment / Cr capital).
• Section totals. Each section's total is minus the movement of its accounts within cash-touching entries. Gain or loss on disposal of investing assets is attributed to investing (named rule, test disposal_proceeds_all_investing).
• Lines. Gross direct-method lines, one per cash-touching entry and section, including credits, so disposal proceeds count.
• Reversals. An original and its in-period reversal net out of the gross lines. Reversal lines are labelled "Reversal of #N", never "Owner distributions" (:1437).
• Supplementary schedule. operating_reconciliation (net income to operating cash), required when the direct method is used (ASC 230-10-45-30; sourced in rules.md).
• Footing. reconciles {sections_sum, net_change, difference}. A nonzero difference is CashFlowDoesNotFoot, an engine error that is never output.
• Description. Tool text (S:2202) is corrected.
• Proof. Lean cashflow_sections_sum_to_cash_change in Statements.lean, derived from the per-entry balance law. Property test (5,000 cases). Kani on the section-sum kernel function.
• Wanderland. FY2026 must foot. It was −2,087.64 vs +612.36; the golden is recomputed by hand.

Defect 7, IIF (ledger-import/src/iif.rs:169,243): DOCNUM = entry_id. Output encoded in Windows-1252; characters outside it are transliterated (deunicode) and listed in warnings.

Defect 21, CPA package IIF and as_of (found in P0, 2026-10-16): the CPA package's general-journal.iif ignores as_of (an as-of package includes entries dated after it); its xlsx and csv files respect it. The IIF export takes the same as_of, and a test pins every file in an as-of package to it.

Defect 22, depreciation through an asset's final month (found in P0 review round 4, 2026-10-17): the depreciation schedule plugs to the full depreciable amount whenever the date it is computed through falls in the asset's final month, even mid-month. A disposed asset's schedule therefore shows full depreciation in its disposal month, and mid-final-month figures are overstated. Resolve from the standard (straight-line, partial months prorated by days, as the rest of the schedule already does), then adjudicate the changed figures in the P3 change log. Related, found in the same round and fixed in P0: the final-month true-up compared the month with chrono's %Y, so assets whose life ran past 9999 (or before year 0) never trued up. Assets whose life runs past 9999 also can't post months after 9999-12 (periods are bounded to years 1-9999); decide in P3 whether to refuse such lives at registration. Also noted: the viewer recomputes a very long-life asset's whole schedule every frame (slow; pre-existing).

Defect 8, tax categories: add_account warns on P&L accounts without a tax category. Needs attention flags all P&L accounts regardless of activity. policy.require_tax_category makes it a refusal.

Defect 9, schedules:

• convention: daily|monthly_even. New schedules use books.schedule_convention, default daily (D-11, decided). Legacy schedules stay monthly_even.
• Shared kernel function prorate_by_days with depreciation. Kani: parts sum to the total; each part equals days × rate within 0.01; the last part absorbs the remainder.
• list_schedules exposes start, end, convention, next and remaining.

Defect 11: parties takes tin_last4 from party.tin_set or W-9 facts.

Defect 12, 1099 worksheet (ledger-core/src/form1099.rs):

• Instruments are added.
• Payments by card or third-party network are excluded and listed under excluded_card_payments (IRS Instructions for Forms 1099-MISC and 1099-NEC, payment-card exception; vendored in docs/spec/sources/).
• A member's personal cash or check through a financing liability stays reportable, because the entity is the payer.
• An unknown instrument on a financing-routed payment is undetermined and raised in Needs attention.
• README wording fixed. The untagged note is quieter: one count plus a tool hint.

Defect 13, assets:

• accumulated_posted vs accumulated_scheduled_through(as_of).
• in_service_date + acquired_date.
• asset.basis_set:
  • tax_basis_723 is the carryover basis (IRC §723);
  • depreciable_basis = lesser of FMV and adjusted basis for personal-use conversion (Treas. Reg. §1.168(i)-4(b));
  • built_in_gain_704c = fmv_at_contribution − tax_basis_723 (IRC §704(c), Treas. Reg. §1.704-3), with §704(c)(1)(C) noted when the result is negative;
  • sec704c_method.
• built_in_gain() (assets.rs:204) is redefined to match.

Defect 14, party shares: resolved uses the line sign convention (debit-positive) plus an explicit direction. Totals take basis: cash|all, default cash, with the basis labelled.

Defect 15: rename_account; show refuses start > end.

Defect 16: one period_defaults(kind, settings, today) used by tools, the GUI and generated descriptions.

Defect 17, odd cent:

• CloseTo::MembersCumulative. Each member's cumulative allocation = round(cumulative net × share); each close posts the delta.
• Extends kernel::apportion (kernel.rs:309) and replaces split_first (shares.rs:197) for closes.
• Kani: exact sum; |cumulative − exact| < 0.01.
• Lean Apportion.lean: bounded-drift theorem.
• Posted closes never change. The cumulative count starts at inception (D-10, decided), so the first close after the upgrade carries any historical true-up of a cent or two, listed in the P3 change log.

Defect 18: not_reportable{reason} is distinct from undetermined.

Tests and accept:

• A named regression test per defect, built from its 2026-10-16 reproduction (anonymized fixture).
• Goldens recomputed by hand.
• GnuCash differential re-adjudicated.
• 0 unexplained mutation survivors in ledger-core and ledger-import.
• The Wanderland change log is adjudicated.

P4: Drafts, reversal as draft, the evidence gate, digest (defects 2, 5, 6)

Scope:

• Core: draft states; entry.draft_state_set, draft_discarded, reversal_drafted, evidence_inherited. reverse_entry_steps (ledger.rs:1355-1380) stops posting inline. check_reversal (ledger.rs:1319) also refuses a second open reversal draft. ledger_core::evidence::requirement is the single gate, used by Store::post_entry (every path), MCP and GUI.
• Exemptions removed: S:561-568, receipt_policy.rs:6, S:2540, GUI books.rs:648. Digest, settings and docs now agree.
• Defect 5: schema v12 columns; list_drafts; discard_draft; set_draft_state; as_of_status plus strict on reports; the CPA package refuses an open draft unless given a reason.
• Defect 6, digest: since/since_seq by posted_seq; as_of; zero-net touched accounts; reconciliation_tracked; never_reconciled; drafts by state.
• Preview: preview_entry plus preview_token on all confirm tools.
• Needs attention: "draft awaiting evidence" and "reversal draft needs evidence", distinct from "draft not posted".

Proofs:

• Lean Step.draftReversal, Step.discard, each with preservation.
• Reachable.reversal_reverses_posted: every posted reversal reverses a posted original, at most once.
• draftsOpen accounts for discard.
• tests/model.rs extended.

Tests:

• reversal_needs_evidence, inherited_evidence_posts, legacy_reversed_replays_identically, discard_unblocks_close, report_warns_on_draft_before_as_of, cpa_package_refuses_open_draft.
• digest_since_is_posting_time (an entry backdated but posted today appears).
• stale_preview_refused; gui_and_server_gate_agree.
• fuzz_op_sequence gains the new ops; store refusal law at STORE_CASES=5000.

Accept: legacy fixtures open; Wanderland has 0 unexplained drafts.

P5: Agent surface complete (B, guidance)

Scope:

• Final connect text.
• books.start v2 (4.2).
• Full prompt set; resource templates.
• Result envelope (next_steps, guards, warnings, head) in call_tool.
• books.journal_history; books.job.
• Correcting a record's source. A convention's citation (or who decided it, or when) can't be corrected today unless its words change too: set_convention with only a new source is refused as "already says exactly that" (found at the Wanderland P1 cutover, 2026-10-17, correcting an unchecked citation). A source-only revision, journaled with its reason; the same for decisions and open items.
• Tool descriptions ≤ 700 characters; handbook complete; URL-mode elicitation where the client declares it.
• docs/mcp-interface.md rewrite (24-95, 580-648, 723-747, 909-931).
• Agent-eval harness ledger-mcp/tests/agent_evals/: scripted, with no LLM in CI. A zero-context transcript that follows only books.start and next_steps must complete onboarding, a receipt-backed post, a draft awaiting a receipt, a reversal draft with inherited evidence, a reconciliation and a month-end close.

Tests:

• Every mutating result has a head and a non-empty next_steps.
• Every guard's remedy tool exists.
• instructions_budget (first 512 characters contain books.start).
• tool_text_lint.
• Golden render per prompt.
• books.start ≤ 8 KB on the Wanderland fixture.

Accept:

• A fresh Claude Code session in /tmp/empty and a Codex session each follow journaled conventions to post an entry. (claude.ai needs the tunnel and OAuth, so its leg is in P9's acceptance.)

P6: Evidence pipeline and scripts retired (defects 3, 4, 10, 20)

Scope:

• Extraction. Crate ledger-extract, run as a sandboxed subprocess:
  • PDF text layer (lopdf);
  • XLSX cells as exact decimal strings from the sheet XML (zip + quick-xml; never floats, fixing verify-sheet.py:118-119);
  • CSV and text;
  • EML via mail-parser;
  • page raster with hayro;
  • no OCR in core for now (D-15, decided): image-only receipts rely on page images plus attestation.
• attachment.text_extracted at attach time, plus a backfill job.
• get_receipt default meta + text, and page_image. Text and page resources. Defect 3 complete.
• Dedup (defect 4): identical bytes return the existing record and add a link; find_attachment; consolidate_duplicates (links move to the first record, duplicates withdrawn with "duplicate of #N").
• Annotations (defect 10): annotate_attachment; engine receipt numbers (next = max + 1); reimbursed derived (entry.settles when given, otherwise FIFO per party on the financing account, labelled derived: fifo).
• Email. attach_email:
  • an embedded PDF is preferred;
  • otherwise a deterministic Typst render of headers and body, with fixed PDF metadata and inline images kept;
  • attachment.rendered is journaled;
  • the .eml itself is never filed.
• Company records (D-20). Categories for notices and correspondence, plans, and history beside formation, legal and the rest; the viewer's Documents page grouped by category and subject; the books dir's company/ folder retired (Wanderland: its files are filed, attachments 73–80, two more after the EIN fix). With extraction, the TIN scan reads PDFs' text too: the own-EIN exemption applies there as well.
• Migration tools (defect 20): compare_reference and record_inventory/check_inventory replace scripts/verify-sheet.py and scripts/drive-manifest.py. eml2pdf.py is retired.

Tests:

• same_bytes_one_record (property: N attaches, 1 record, N links).
• get_receipt_default_has_no_bytes, page_image_is_png_of_page, inline_base64_requires_sha.
• extraction_deterministic, eml_render_deterministic.
• xlsx_cells_are_decimal_strings (property).
• extractor_sandboxed (network and filesystem escape attempts fail).
• compare_reference_detects_one_cent.
• fuzz_extract_pdf, fuzz_extract_xlsx, fuzz_eml.

Accept:

• get_receipt default output is < 8 KB for every Wanderland attachment (the earlier audit reached 415K tokens).
• Wanderland 5.6 P6 checks: 0 differences, 0 inventory gaps.

P7: Vault v2 and the human channel

Scope:

• ledger-vault v2:
  • HPKE sealing;
  • keyring.json with keyslots: passphrase (the owner passphrase from P2), recovery key, passkey PRF, member_passkey;
  • rekey;
  • W-9 files sealed.
• Events: vault.created, vault.rotated, vault.keyslot_*, vault.resealed. Verify checks the public-key sha.
• Human pages: /h/tin/{party}, /h/w9/{party}, /h/unlock, /h/tin-view, /h/download (CPA package and 1099 worksheet with TINs, W-9), keyslot management.
• Tools: request_tin_entry, set_w9_facts.
• Removed from the MCP: set_tin, set_w9 tin|w9_file_path, include_tins, all of them.
• Scanner: pattern-based TIN scanner on every result.
• GUI: in-process passphrase unlock (3.6): it reads the wrapped keyslot and the sealed record from the data root read-only, unwraps, copies to the clipboard only, and zeroizes. No socket.
• wanderbooks vault init|rekey.

Tests:

• no_mcp_output_contains_full_tin (session canary fuzz).
• unwrap_only_in_human_handler; vault_pubkey_swap_detected_by_verify; reseal_preserves_last4_and_kind; cpa_package_with_tins_human_only.
• Lost passphrase is recoverable with the recovery key.
• GUI tin_copy; gui_unlock_zeroizes (no plaintext TIN or private key left in the GUI's memory after the copy).
• Mutation testing on ledger-vault.

Accept:

• The Wanderland K-1 member worksheet and 1099 worksheet with TINs, produced through the human link, match the P0-era output byte for byte apart from timestamps.
• No vault key material remains on disk except the wrapped keyslots in the data root.

P8: Audit, attestations, access-log tooling

books.audit (ledger-core/src/audit.rs plus the store's evidence view; deterministic; no LLM; run as a job):

• Integrity: chain, projection and blobs; access-log chain; vault public-key sha.
• Statements: TB balances; A = L + E; P&L = current earnings; cash flow reconciles; cash equals the last statement for each tracked account; reconciliation coverage.
• Evidence: the gate holds over every posted entry; legacy_reversal_exempt is informational; no drafts dated on or before through; duplicates.
• Closes and schedules: closes in order, with member deltas to the cent; schedules and depreciation posted through.
• Assets: register = cost accounts; tags and basis present.
• Tax and parties: tax categories; 1099 payees with W-9 or TIN and their kind; party policy.
• Settings and freshness: settings problems; 2100 aging; backup freshness.
• Attestations: coverage against the bar.

Output: a workpaper (JSON plus Typst PDF) filed as a workpaper document, and audit.run journaled. It is idempotent on (through, through_seq, program_version).

Attestations: attest_receipt, review_entry and attest_period.

• verified (principal, client_id) is kept separate from asserted (model, effort, adversarial, agents).
• The engine cross-checks extracted amount and date against the entry; a mismatch never counts.
• A period attestation requires an audit.run at the current head.
• counts is derived against policy.attestation_bar in force at that seq, so a bar change applies only going forward.

Needs attention items: "month-end attestation due" after each close; "full audit due before CPA handoff" (export_cpa_package refuses without a counted full audit unless given a reason, per policy.cpa_package_requires_audit = refuse; D-9, decided); "annual audit due". Each states the bar.

Tests:

• audit_is_deterministic (same head gives the same sha).
• audit_detects_each_seeded_defect (one fixture per check).
• below_bar_not_counted, bar_change_is_prospective, amount_mismatch_never_counts, stale_head_period_attestation_refused.
• Lean: counting lemma (counted ⇒ meets the bar at seq) as a decidable predicate.

Accept: an injected fixture with an unfooted cash flow, a missing receipt, an open draft and a duplicate blob produces exactly those findings.

P9: Self-host on another machine, and remote access

This is the documented path for anyone who wants mechanical enforcement, and it is how claude.ai on the web reaches the books. Multi-tenant hosting is not built here (section 11).

Scope:

• Self-host recipe: the same binaries on a machine the owner controls (home server, NAS, VPS), under system units and a dedicated account. wanderbooks-server.service with IPAddressDeny=any (loopback allowed; when the built-in authorization server fetches CIMD documents, D-7 a, connect to port 443 only, with private and link-local ranges denied), seccomp @system-service and Landlock; the archive unit with IPAddressAllow limited to its configured targets; an encrypted volume; Caddy for TLS. A container image is an alternative on that machine. books.start reports isolation: "service_user (enforced)".
• Moving books there: wanderbooks fetch from the desktop server, then books adopt on the self-host machine, with the head check. Adopting an archive clone works the same way.
• Remote access: wanderbooks tunnel --book <book> (a Tailscale Funnel or cloudflared recipe). The static bearer over TLS for header-capable clients (Claude Code, Codex). OAuth 2.1 (3.3) for claude.ai and ChatGPT, built in (D-7 a) or delegated (D-7 b). OAuth is forced on whenever the tunnel is public. The Origin allowlist gains https://claude.ai.
• Remote viewer: replica routes, books:view, Snapshot::from_lines, GUI --books <url>, and /replica/events for books.show and presence (3.6). The replica carries a minimum-version header and no keyslot material.
• Remote people: books.invite {kind: cpa|member|viewer, email} sends a passkey enrolment link; the cpa role is read, view and archive. /h/ pages are served over TLS behind a passkey or the passphrase.
• File inputs: MCP App upload widget (an app-only tool); openai/fileParams.

Tests:

• agent_uid_cannot_read_tenant, rerun against the recipe's deployment.
• self_host_adopt_same_head.
• OAuth: PRM and 401, audience, PKCE, exact redirect, iss, CIMD SSRF guard, step-up; an external Origin, Host and CSRF scan.
• replica_snapshot_equals_store_snapshot; replica_carries_no_keyslot; fuzz_replica_stream.
• An external security review of the built-in authorization server before the remote path is opened publicly (not needed under D-7 b).

Accept:

• claude.ai custom connector via CIMD → books.start → upload through the drop page → post → visible in a replica GUI on another machine.
• codex mcp login works, and the static token works over TLS.
• The audit and the CPA package each finish in < 60 s on Wanderland, or return a job handle.

P10: Acceptance, the full Wanderland re-audit through the MCP alone

Run from clients that hold only a URL and a credential: Claude Code started in /tmp/empty, Codex, and claude.ai through the tunnel if a self-host machine (T2) is running by then; otherwise the re-audit runs from Claude Code and Codex only, and the claude.ai leg is recorded as not applicable. The agents use the tools alone. On the desktop (T1) this separation is advisory, because the agents run as the same user as the server: the evidence is the access log plus session transcripts that never read the data root or name its path. If Stephen runs a self-host machine (T2) by then, the re-audit runs against it, and the separation is enforced.

1. books.audit scope=full through=<month-end> and scope=cpa_handoff. Every finding is fixed through journaled corrections: reversal drafts with evidence, annotations, decisions. Legacy reversals posted without their own evidence inherit the original's with inherit_evidence (D-12, decided).
2. Every receipt is attested from get_receipt text plus page image by a pair at the bar: high reasoning effort, adversarial, at least 2 independent verifier agents (D-9, decided). No base64 enters context.
3. review_entry for every posted entry; attest_period monthly since formation and cpa_handoff annually.
4. Each of the 22 defect reproductions (20 from the 2026-10-16 audit, and defects 21 and 22 from P0) is re-run, and each shows fixed.
5. compare_reference against the Sheet as of 2026-10-11 shows 0 differences. check_inventory against the Drive listing shows 0 gaps.
6. CPA package: no TINs through the agent; with TINs through the human link.
7. The head is handed to Stephen and verified against a fresh fetch with verify-archive --expect-head.

Exit criteria:

• Zero failing workpaper checks; cash flow difference 0.00.
• 100% of receipts and posted entries carry a counted attestation, and 0 disagree.
• The access log shows every action under the right principal. No transcript reads the data root or names its path; the only other reader is the read-only viewer.
• No result carried a full TIN or more than 256 KiB of inline bytes.
• Agent context on receipts never exceeded 100K tokens.
• Stephen's sign-off is journaled as decision.recorded.

P11: One app for Windows, Mac and Linux (D-19, D-22, D-24)

Scope:

• Tooling: cargo-packager (D-25). Its cargo packager builds Wanderbooks.app and the .dmg, the NSIS setup .exe (in its default CurrentUser mode: no admin, metadata under HKCU), the .deb, the AppImage, and the pacman PKGBUILD the AUR package starts from; cargo-packager-updater updates the formats that update themselves (app, nsis, appimage; wix too, if an .msi is ever made). It has no .rpm, so cargo-generate-rpm makes that. Both tools are pinned in mise.toml, like every tool. Checked 2026-10-18 against its source (packager 0.11.8, updater 0.2.3, both pre-1.0): the updater verifies each bundle's minisign (Ed25519) signature against one public key and by default takes only a newer semver than the running one. It has no expiry, no second key and no key rotation, so our signed release manifest (below) is checked first, and the bundle's own minisign signature after it; the primary release key is the minisign key. P11's first step is a short trial of all six formats on clean machines; anything it can't meet goes in the change log before we build around it.
• macOS: a .dmg holding Wanderbooks.app (the one executable inside the bundle), signed with the company's Developer ID, notarized and stapled. Drag to Applications, or ~/Applications for a standard user who can't write /Applications; no admin password. While macOS runs the app translocated (straight from the .dmg or Downloads), it says to move it first and refuses to connect agents, so no temporary path lands in Claude's or Codex's config. The app updates itself in place.
• Windows: a per-user installer that asks for no admin password: a signed setup .exe into the user's app folder; an .msi only if a managed install ever needs one. The app updates itself. Signing through Azure Artifact Signing if the company or Stephen qualifies, else an OV certificate; SmartScreen warnings fade as the download builds a reputation.
• Linux: Arch (an AUR wanderbooks-bin package), Debian/Ubuntu (.deb and our signed apt repository), Fedora (.rpm and our signed dnf repository), each installed and updated by the system's package manager (with sudo, as every package there is); and an AppImage that updates itself and needs no admin password, for every other distribution. The packages install the one executable, a .desktop entry and the icon.
• One updater rule set (D-24), whatever the tooling:
  • Every update is verified twice: against our own release key (Ed25519 over a release manifest listing each file's sha256) and the system's code signing. Either failing refuses the update; nothing is half-installed.
  • The updater restarts the books, it doesn't close them (3.9): update.lock, a clean stop after the request in progress, an atomic swap, a restart from the new executable; the viewer reopens and the agent bridges reconnect by themselves.
  • When updates happen: the host checks for one daily while the books are open, downloads and verifies it, and stages it; it is applied at the next restart the owner accepts in the app, or by the helper just before it next starts the host. An install whose books are never opened is never touched.
  • Format changes are the server's gate (3.9, format_upgrade_pending), not the updater's: the owner consents in the app after a verified backup with the keys. A failed update rolls back to the previous app, which can still open the books as long as no newer format was written. After consent there is no rollback for that book: only restoring the pre-upgrade backup as a separate book, which shows how many entries it lacks (3.9).
  • Updates never start during a long job (a CPA package, an audit, an extraction backfill). Multi-call work like a reconciliation is journaled as it goes, so a restart between calls loses nothing.
  • Release keys. Two Ed25519 keys, a primary on a hardware token held by the owner and a backup kept offline; CI builds and code-signs but holds neither, so it cannot sign a manifest. Rotating or revoking a key is a statement signed by the other. Each manifest carries a version that only increases and an expiry: from the feed, an older version than the one installed is refused (no rollback attack), and so is an expired manifest (no frozen feed). Going back to the kept previous app is a local action by the owner, not a feed update, and stays allowed.
  • Package-managed installs (AUR, apt, dnf) are updated by the package manager, with its own signatures (our repository keys) and sudo as usual on Linux; our updater stays out, and wanderbooks update refuses there. The host notices the new executable and restarts when idle (3.9); the format gate still protects the books.
• Connecting agents from the app: the menu offers "Connect Claude Code" and "Connect Codex" (P2's connect, with the absolute path of the installed executable, which updates keep stable), so no one edits a PATH.
• Data root in each system's usual app-data folder (Application Support, %LOCALAPPDATA% (never the roaming profile), ~/.local/share), as in 3.4 and 3.9.
• Release builds and the full test suite on all three systems in CI; package builds for Arch, Debian and Fedora in their own containers.
• The viewer menu of P2 (back up, export, restore, new books, close the books, connect an agent) is the app's whole surface beyond the viewer; there is no separate launcher app.
• Costs (company expenses, recorded with their receipts): the Apple Developer Program (the company's enrollment, attachments 76 and 77); Windows code signing (Azure Artifact Signing, about $10 a month where eligible, or an OV certificate, about $150 to $300 a year).

Tests: install_needs_no_admin (dmg, Windows installer, AppImage, clean machines); translocated_app_refuses_to_connect; manifest_rollback_and_expiry_refused; key_rotation_statement_verified; package_upgrade_restarts_host; update_is_atomic; failed_update_rolls_back; unsigned_update_refused (bad release-key signature, bad code signature, a file whose sha256 differs from the manifest: each refused, nothing changed); update_closes_books_cleanly (during a burst of posts; head verifies after); update_waits_for_long_jobs; format_change_update_backs_up_and_asks (declining leaves the books untouched and openable by the old version); bridge_survives_update; linux_packages_install_and_upgrade (AUR, apt and dnf repositories in clean containers; AppImage self-update); server_runs_with_viewer_closed; P2's restore tests on all three systems.

Accept:

• On a clean Windows and Mac machine, and on Linux with the AppImage: install, open, onboard and post a first entry with no terminal and no admin password. On Arch, Debian and Fedora: the same after the package manager's usual install.
• An update, on each system, leaves every book's head and goldens unchanged, and an agent session open across it carries on.
• A backup made on one system restores on each of the others.

---

9. Risks and mitigations

1. Journal forward compatibility. Old GUIs or CLIs cannot read v2 events.
   • The P0 NewerJournal gate ships first. The local GUI reads the journal directly, so it goes through the same gate.
   • One executable (D-22): an update replaces it whole; the server's format_upgrade_pending gate (3.9) protects the books however it arrived.
   • The replica (P9) carries a minimum version.
   • Fixtures from every phase are kept.
   • Downgrade is impossible after the first v2 event, so back up first (P1 says so).
2. The settings migration shifts numbers. Byte-identical goldens gate P1. company.members effective dating must reproduce the close_to history exactly.
3. P3 fixes change Wanderland's reports and tax output. Every difference is hand-adjudicated in the change log, and the 1099 and 704(c) changes are shown to the CPA. Posted entries never change. The cumulative close rounding counts from inception (D-10), so the first new close may carry a one- or two-cent true-up; it is listed in the change log.
4. The P2 cutover is large and could disrupt daily use.
   • The scripted adopt checks the head hash.
   • If Stephen agrees (Q-3), the old copies move into the data root's legacy/ area. Nothing is deleted.
   • Rollback is documented.
   • The final runs of verify-sheet and drive-manifest are filed before cutover; Drive deletion waits for P6.
5. The P2–P7 interim: TINs still cross the MCP on set_tin/set_w9, with no added prompt (owner decision: no requiresUserInteraction).
   • Mitigation: P7 is scheduled before mid-January (1099s are due Jan 31, K-1s by Mar 15). TIN-bearing outputs are human-only from P2.
6. Desktop isolation is advisory. A process running as the human, including an agent that deliberately hunts, can read the data root, the agent token and the wrapped keyslots.
   • TIN plaintext still needs the passphrase.
   • The path is never named, the root sits outside every project directory, and every place that reports isolation says "advisory".
   • The server's own Landlock and seccomp are never presented as protecting the books from the agent.
   • Enforcement is the self-host deployment (P9), tested in CI from P2.
7. The books are open only while something holds them (D-21, D-23: the app, an agent session, a serve terminal; no background service).
   • An agent session opens them itself through its bridge, so it needs no reconnect. A client connected over HTTP instead of the bridge holds no lease and needs them already open.
   • The viewer reads the data root directly, so it works even if the server can't start; "Restore…" and "New books…" say why they can't run then.
   • Backups run only while the books are open. The books change only then, so nothing goes unbacked; the archive process pushes anything left over, and a drill that fell due, at the next open.
   • The host outlives the opener that started it, by design, until the last lease ends; it is never left running with no holder for more than 10 s. A crash or power loss is what the append-only journal already survives.
8. The OAuth authorization server is security-critical code written in-house (rmcp has no server-side auth). It is needed only on the self-host remote path.
   • Small surface: passkeys only, no password grant.
   • Built on audited crates (webauthn-rs, oauth2 types); fuzzed; externally reviewed before the remote path is opened publicly.
   • Alternatively an external IdP (D-7).
9. Client variance.
   • claude.ai: no elicitation, about 150K-character results, 240 s per call.
   • Cursor: legacy protocol versions only.
   • Codex: a 512-character budget.
   • The resource_link content type is undocumented, and the files extension is experimental.
   • Mitigations: links repeated in text, both protocol eras served, jobs for long work, the drop page, and an adapter for io.modelcontextprotocol/files once it stabilizes.
10. Extraction quality. There is no OCR in core (D-15), so image receipts rely on page images plus attestation. The extractor version is journaled, and re-extraction appends events and never rewrites.
11. Attestation method is self-reported. The bar is a policy on claims by an authenticated client. Verified and asserted fields are separated, and the deterministic cross-checks are the hard floor.
12. Performance. One mutex per book serializes writers. Mitigations: reader snapshots, spawn_blocking, jobs, SSE backpressure, the blob LRU.
13. server.rs size (8,529 lines). It is split per tool group as each phase touches it, to keep review cost bounded.
14. Tool surface churn (preview_token, removed parameters). The confirmed alias and the removed-tool errors that name their replacement last one release, and the agent-eval harness catches guidance regressions.
15. Proof obligations (cash-flow footing, cumulative drift, reversal-draft transitions) may take time. A failing proof is a finding and blocks its phase by design.

Hosted-service risks (operator-served unwrap code, the legal exposure of hosting SSNs) are in section 11.

---

10. Decisions

10.1 Settled

The owner decisions of 2026-10-16 (at the top of this document) replace the former questions D-1 (local isolation default), D-6 (hosting timeline), D-8 (posting friction) and D-14 (viewer on the desktop). The engineer settled the following from the standards:

#	Question	Decision
D-5	Company EIN	(a) A journaled company.ein with sensitivity identity: printed on every 1099, masked in books.start, full in packages.
D-9	Attestation bar default	(a) Receipts and month-end: reasoning effort ≥ high. Annual and CPA handoff: adversarial verification with ≥ 2 independent verifier agents. No model allow-list. The CPA package refuses without a counted full audit unless given a reason (policy.cpa_package_requires_audit = refuse).
D-10	Odd-cent cumulative apportionment start	(a) From inception, so the next close carries any historical true-up of a cent or two; lifetime drift stays under one cent.
D-11	Default proration for new prepaid schedules	(a) Daily, matching depreciation; existing schedules stay monthly_even.
D-12	Legacy reversals already posted without their own evidence	(a) During the re-audit, link the original's receipts with inherit_evidence, so the audit is fully clean.
D-13	Wanderland timezone	(a) company.timezone = America/Denver.
D-15	OCR for image-only receipts	(a) None in core for now: page images plus agent attestation.
D-16	CPA access to TINs	(a) To start, the owner prepares and sends a single-use human link each time.
D-18	dev-stdio	(a) Kept permanently for tests and demo. It refuses inside the data root and is never offered by connect.
D-19	One app for Windows, Mac and Linux (owner, 2026-10-17)	Planned: backup and restore in P2, the app itself in P11. One installer and auto-updater per system. The server, the viewer and the CLI ship and update together; since D-22 they are one executable that runs each as its own process: the agent needs the server while the viewer is closed, and the viewer stays read-only as a separate process. No separate launcher app, which would be a third program and a second writer (the helper of 3.9 is a mode of the one executable, not an app). The viewer is the app's face and gains menu items: "Export for CPA" (read-only; the viewer does it) and "Back up now" (handed to the archive process, 3.9), "Restore…" and "New books…" (they change books, so the viewer hands them to the server), and the CPA package with TINs through the human path (P2 /h/, P7 vault). The books live in each system's usual app-data folder (the data root of 3.4): hidden, not locked; a little more protected on macOS. Backups must restore, into an existing install or a new one, proven before use and never destructive (3.7).
D-20	Company records (owner, 2026-10-17: "It's just too damn convenient to keep it all together in one place.")	Every company document goes into the books, not only what the CPA needs: formation papers, registrations, plans, notices, drafts, history. Done for Wanderland 2026-10-17 with the existing categories; the filing scan passes the company's own EIN printed 2-7 (rules.md B-26). P6 adds what makes it pleasant (below).
D-21	How the local server runs (owner, 2026-10-18: "Not sure I want a background service at all. Running in the foreground for now works for me.")	Started by hand in a terminal, not a background service: wanderbooks serve opens the books (the server and its archive process) and runs until stopped; agents connect over HTTP while it runs, several at once; Ctrl-C or closing the terminal closes the books cleanly. Nothing is installed to run in the background: no systemd unit file, no LaunchAgent, no socket activation, no login autostart. The viewer works with the server stopped (it reads the data root). Amended by D-23 (same day): the books also open when the app or an agent starts, and close when the last of them ends.
D-22	One app or several (owner, 2026-10-18: "My objective is simplifying installation and updates.")	One app, one executable, separate processes. wanderbooks is the only program installed; each role is a mode of it, run as its own process: the viewer (what opening the app shows), the books server and its host, the agent bridge (wanderbooks mcp), the archive process and the extractor. One thing to sign, notarize, ship and update. Mixed versions are still possible across a swap, so the host starts its children from its own executable and every handshake carries the version (3.9). The viewer's read-only rule never rested on a separate file: ledger-gui already links ledger-store and stays read-only through Snapshot and tests/read_only.rs. As its own process it keeps that, and on Linux it also confines itself read-only (Landlock). Each mode confines itself at start. The crates stay as they are; the executable is a thin dispatcher (P2). One exception: a server-only build (the gui feature off) for self-host (P9), so a headless machine carries no window libraries.
D-23	When the books are open (owner, 2026-10-18: "Also when an agent starts")	Amends D-21. The books are open while anything that opened them runs: the app, an agent session (its bridge opens them, windowless, for the session), a terminal running wanderbooks serve, or a CLI command. Each holds a lease on the host's lease-only socket, so a crashed holder lets go by itself; local agents speak to the server over a peer-checked local socket, never TCP (3.9). The first opener starts the one host; later ones attach; when the last lease ends the books close 10 s later, cleanly. "Close the books" ends every lease at once. Still no background service: nothing starts at login and nothing runs after the last holder. An agent session started with the books closed needs no reconnect (P2).
D-24	Installers and updates (owner, 2026-10-18: "A dmg for macOS, msi or whatever for windows, and packaged for Linux distributions. Win and Mac with updaters.")	macOS: a signed, notarized .dmg; the app updates itself. Windows: a signed per-user installer with no admin prompt (.msi only if a managed install needs one); the app updates itself. Linux: AUR, .deb with our apt repository, .rpm with our dnf repository (all updated by the package manager), and a self-updating AppImage. Every self-update is verified against our own release keys and the system's code signing; Linux packages are verified and updated by their package managers. An update restarts the books cleanly. A newer books format is the server's gate whatever the install: read-only until the owner consents, after a backup with the keys (3.9). "No admin password" holds for the dmg, the Windows installer and the AppImage; Linux packages use sudo as usual. Details and tooling in P11.
D-25	Packaging tool (owner, 2026-10-18: "Cargo packager looks good. Would like to use that.")	cargo-packager and its updater (crabnebula-dev, MIT/Apache-2.0) for the .app/.dmg, the per-user NSIS installer, .deb, AppImage and the AUR's PKGBUILD; cargo-generate-rpm for .rpm, which it lacks. Our release manifest (two keys, rotation, a version that only increases, an expiry) wraps its single-key minisign check (P11).

10.2 Deferred

• D-7. OAuth for remote access. This now applies only to the self-host remote path (P9). The options: (a) build a minimal authorization server into wanderbooks (passkeys, CIMD/DCR), self-contained and portable for self-hosters, which is recommended; or (b) delegate to an external IdP (Authentik, Ory, Keycloak) and only validate tokens. Settled when P9 starts.
• D-17. Remote file intake beyond the drop page (an email-in address) is deferred with the hosted service (section 11). P9 ships the MCP App upload widget only.

10.3 To ask Stephen at the P2 cutover

These are the only open owner questions. Ask them just before the move, one at a time, in plain English.

Q-1. Where should the automatic backups go? The books back themselves up after every change. Where should that copy live: in a private git repository you name (for example on your own git server), or on another disk? Either way, the backup includes the whole history and the sealed tax ID numbers, and it is locked with a key only you hold.

Q-2. Should the papers in the company/ folder be filed into the books? These are the formation papers, notices and company history. Once they are in the books, every agent and the viewer can find them, and if you later run the books on your own server, claude.ai and your CPA can reach them too. If they stay as files, they live only on this computer. Recommended: file them.

Answered 2026-10-17 (D-20, Stephen): "I would like to have all the non books docs be able to be in there too." Every company/ record was filed at the P1 cutover (attachments 73-82, linked to the company); only the local copies remain, until P6 moves the Drive manifest in. Don't ask Q-2 again.

Q-3. After the move, should the old copies of the books leave the project folder? The project folder still holds the old journal and receipts (books-data/), the old sealed tax ID numbers (vault/), and the folder's git history, which contains the journal and receipts too. Recommended: move them into the private folder's legacy area. That is what "hidden away" means; otherwise an agent working in the project folder can still read the old copies. Nothing is deleted.

For the engineer: Q-1 was D-3, Q-2 was D-4 and Q-3 was D-2. Q-1's technical side is settled: archive.git is seeded from the existing git history, filtered to the journal and blob paths, includes the vault ciphertext, and is age-encrypted as a whole on push (3.4, 5.5).

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11. Later: hosted service (not built in this plan)

A paid, multi-tenant service in which an operator runs the books for customers. P0–P11 build none of this. It is recorded here so the design stays compatible with it.

Shape.

• Per-tenant pair. front (ledger-mcp front --tenant <t>, user ID wb-f-<t>) does OAuth 2.1 (3.3), passkeys, consent, the human pages and token validation; its Landlock denies books/, so it never reads tenant disk. worker (ledger-mcp worker --tenant <t> --socket, user ID wb-t-<t>, DynamicUser=) serves the MCP, uploads, downloads and the replica for its own tenant only, and learns identity only from X-WB-Principal on its 0660 socket. Caddy handles TLS and routing and holds no authority. No component holds authority across tenants. Both roles ship in one binary.
• Workers run from the systemd template wanderbooks-worker@.service with seccomp @system-service and Landlock; a container image is the alternative. The archive unit runs per tenant.
• Data root /srv/wanderbooks/t/<tenant>, with the 3.4 layout, on a LUKS volume per tenant. Books are at https://host/t/<tenant>/b/<book>/mcp. Each tenant's front is its own issuer.
• Tenant provisioning, quotas and invitations.

Vault model B (required before any paid launch). Unwrap happens on the client, in the signed native viewer or in reproducible WASM with a published SRI manifest. Keyslot material is released only inside an unlock exchange authenticated by a passkey assertion. The web viewer is egui→WASM on ledger-core + ledger-view; it needs a pure-Rust evidence projection (no SQLite), reproducible builds and a published SRI manifest. The signed native viewer is the reference implementation. Hosting is not marketed as "operator cannot read TINs" until model B ships, because model B depends on operator-served code.

Tamper evidence. Opt-in head delivery by email or webhook, and an optional transparency witness.

File intake. A per-book email-in inbox (D-17).

Threats specific to hosting.

Adversary	Goal	Controls
Other tenants	cross-tenant access	per-tenant user IDs and processes; Landlock; per-tenant issuer; token audience is the book URI; capability handles keyed <sub>:<book>:<256-bit>
Hosting operator (assumed hostile)	read TINs; rewrite or fork history	TINs: HPKE to a journaled public key; customer keyslots; model B before any paid launch. History: head in every result, quiet-period handoffs, emailed heads (opt-in), verify-archive --expect-head, optional witness. Ledger confidentiality is not provided (the server is the engine); the terms say so; self-hosting is the zero-trust option

Customer flow.

1. Sign up with a passkey and create books (tenant provisioned: front, worker and archive units, plus a volume).
2. Vault ceremony: passphrase, recovery key shown once and confirmed saved, optional passkey PRF.
3. "Connect" cards for claude.ai, Claude Code, Codex and ChatGPT. claude.ai: Settings → Connectors → Add custom connector → https://books.example.com/t/acme/b/main/mcp; OAuth: passkey, then consent with scope checkboxes.
4. Optional: archive to the customer's own git or S3; opt-in head emails.
5. Viewer: wanderbooks gui https://books.example.com/t/acme/b/main (OAuth books:view, in memory), or the web viewer.
6. Verify at any time: wanderbooks fetch … && wanderbooks verify-archive <dir> --expect-head <hash>.
7. Leave: download the archive bundle, books adopt it on a self-host, and get the same head.

Before launch.

• Tests: tenant_isolation; front_cannot_open_books (Landlock); client_side_unwrap_server_never_sees_plaintext (instrumented); wasm_viewer_equals_native_view; witness_detects_fork; cross-tenant → 401/403.
• An external security review of the authorization server.
• Load: 1,000 idle and 50 active tenants per node, p95 non-report latency < 300 ms.
• The directory review checklist passes.
• Compliance: state breach statutes and the FTC Safeguards Rule apply to stored SSNs, and data residency matters, so counsel is needed before launch. Retention is 7 years. Account deletion is crypto-shred plus purge.