docs: U0b landed; books.start and the viewer share one attention engine

plan/STATUS.md

@@ -160,6 +160,23 @@ MCP handlers only in its own group file** (`documents.rs` for S4.4/S6,
 `drafts.rs` for P4, `evidence.rs` for P6, `audit.rs` for P8); `server.rs`
 keeps the router and the shared helpers.
 
+**2026-10-27: U0b landed (`26d3a994`).** Needs attention is one engine in
+`ledger-package::attention`, read by the viewer and by `books.start`; the
+viewer's module only maps a target to a route. The review found and the
+unit fixed a parity gap: the server had passed `Integrity::default()`
+("healthy") while the viewer computed its own, so a damaged book showed
+the `database` or `stored_files` item to the human and not to the agent.
+`books.start` now runs the real check, and
+`the_viewer_and_books_start_see_the_same_attention` proves the two lists
+equal item for item on a clean demo, a written book, that book with a
+missing receipt blob, and that book with a tampered projection. Cost
+measured on the demo books: 138 distinct blobs hashed, `books.start` cold
+287 ms / warm 256 ms in a debug build on a loaded machine; no cache was
+added, and the As-built records that a book with thousands of large scans
+is where one would go. `Attention` also carries the prompt (the viewer's,
+so there is one copy) beyond the plan's sketch, and `PackageBooks` gained
+four read methods rather than a new trait. `just check` green.
+
 
 The 2026-10-16 audit of the first company's books (62 verified findings,
 20 engine defects) and the design discussion that followed produced

plan/served.md

@@ -813,7 +813,7 @@ One row per unit of work. A unit is what one engineer takes into one git worktre
 | P4b S2 | Read tools and viewer pages | landed 2026-10-24 (`7d2bf0b7`, `b7b7f171`) | | | | |
 | P4b S3 | The invoice PDF | landed 2026-10-24 (`c1f9001c`) | | | | |
 | U0a | Split `server.rs` by tool group | landed 2026-10-27 (`45396bdc`) | none | U0b, U0c, S4.1, S4.2, S7.1 (core steps only) | none | 3-4 |
-| U0b | The attention engine over `PackageBooks` | not started | none | U0a, U0c, S4.1, S4.2 | none | 4-6 |
+| U0b | The attention engine over `PackageBooks` | landed 2026-10-27 (`26d3a994`) | none | U0a, U0c, S4.1, S4.2 | none | 4-6 |
 | U0c | `docs/testing.md` sections for S1-B, S2, S3; `docs/mcp-interface.md` cleanup of stale P4b notes | landed 2026-10-26 (`198aa2a1`) | none | everything | none | 0.5-1 |
 | P4b S4 | `documents_v2`: numbers, terms, line accounts, snapshots, preview and confirm, the issued PDF filed, party email and terms, invoicing settings | in progress: S4.1 landed (`13282cf8`), S4.2 landed 2026-10-27 (`bf91c5a7`); S4.3-S4.5 open | S4.1 and S4.2 need nothing; S4.3 needs S4.1, S4.2; S4.4 needs U0a, S4.3; S4.5 needs S4.4 | S5 (after S4.2), S7 (core after S1), P6, P9a, P11a, P13 | `documents_v2` (one upgrade after S7, D-52) | 12-16 |
 | P4b S5 | Sent tracking | not started | S1; S4.2 for the defaults (works without it, see the unit) | S4.3 onward, S6 | `documents_v2` | 3-4 |