Every run since P9a landed failed at the first adoption with
"/tmp/fixture: Permission denied": the copies were owned by the runner
(cp -a keeps the checkout's ownership) and the server account, which
adopts them, could not take the source's lock. Both copies are now owned
by the server account; the agent account keeps read access to the
source's journal, which the test compares the moved books' head with.
P9a's Done-when 1 (the job's first green run) is checked on this push.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HS8WZziDnyxunC23MUxrLp
The books can live on a machine of the owner's own (plan 3.8, 8.2 P9a,
D-51). Three things make that honest instead of nominal:
- `--isolation same_user|enforced` sets `server::Isolation`, carried
through `Served` and `BooksServer` to `books.start`. Locally the books
stay `same_user (advisory)`; under the self-host unit the server is told
`enforced` and reports `service_user (enforced)`. The server never
guesses, and the literal it used to report is gone.
- `--http [ADDR]` binds the same MCP router on loopback (default
127.0.0.1:7411) beside the Unix sockets, before the ready line, for the
TLS proxy or tunnel in front of the server. It is the same bearer door
and the same graceful close; a failed bind is reported and is not fatal
(3.9). `serve` carries both flags through the host, so the system unit
can ask for them once.
`deploy/wanderbooks-server.service` is the unit: a dedicated account, a
0700 data root, `ProtectSystem=strict`, no seccomp or Landlock (D-32), and
loopback-only networking. `deploy/README.md` is the recipe: install, setup,
move the books by `books adopt` with its head check (D-31: a copied book
is the transport), mint a bearer token, put Caddy or Tailscale Funnel in
front of the loopback door, and point Claude Code and Codex at it.
The two-account CI job (`.github/workflows/two-user.yml`) makes the
deployment and runs `crates/ledger-cli/tests/two_user.rs` as another
account: `agent_uid_cannot_read_tenant` proves the tenant root and its
journal are refused, then reads, writes, uploads, files, exports and
verifies over HTTP with the bearer (in a second book, so the moved books'
head is not advanced); `self_host_adopt_same_head` compares the moved
books' head and event count with the source clone's.
`isolation_label_is_enforced_under_the_unit` runs everywhere, including
the unit-file read that keeps the recipe from drifting.
Accounting reason for the shape: nothing here changes an entry, a report
or a figure. It changes who can reach them: the move is lossless and
verifiable at the head, and the boundary is the operating system's, not a
promise in our text. No journal code, kernel function, Kani harness or
Lean step is touched, so `just prove` is not required.
No go-ahead needed: no new journal feature or event; the live books are
unaffected.
swaitsandClaude Fable 5.1