CB-WP-0033: a game is the unit

make trials reported "positions unreachable: 4, target 0 — the recording
exists but the position moved". All four were false. A recording holds one
hash, the final state, and reachability asked whether the note's hash was
in that file — so a mid-game note could never match, and a post-game note
from any but the last game could not either. Instance 8 of the ADR-0018
family: vary only WHEN a note was written and the answer flips, with
nothing having moved.

The root cause was not the metric. play again reused state belonging to a
game: it overwrote the previous game's recording (data loss), never
cleared the journal (game 2's log opened with game 1's commands), and so a
note's command index pointed into a recording without those commands.
Fixing reachability alone would have gone green while a session still
destroyed its own evidence.

A note now binds by (game, after) — an index into the recording's own
commands list, which a reader can replay to. The hash keeps a job as the
integrity check at the end of a game, where it can actually fail. Game 1
keeps the path it was given, so GameDesign §5's documented invocation is
unchanged; later games get -2, -3 and nothing is overwritten. Legacy
5-column logs stay readable and are reported as legacy, never as orphans —
an unsubstantiated orphan claim is the defect being fixed.

All three fixes mutation-proven, including at the call site via a real
two-game session.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

workplans/CB-WP-0032-the-comments-in-the-account.md

@@ -3,6 +3,7 @@ id: CB-WP-0032
 kind: product
 title: "The comments in the account"
 status: done
+state_hub_workstream_id: "71d744f9-7e40-49c3-994e-f3fb007a1430"
 ---
 
 # Purpose
@@ -74,6 +75,7 @@ blaming a missing block for every failure.
 id: CB-WP-0032-T01
 status: done
 priority: high
+state_hub_task_id: "31f60440-e049-45f7-99fa-87c01c00adb7"
 ```
 
 **Controls:**

workplans/CB-WP-0033-a-game-is-the-unit.md

@@ -0,0 +1,99 @@
+---
+id: CB-WP-0033
+kind: product
+title: "A game is the unit"
+status: done
+---
+
+# Purpose
+
+```
+structural tier  M   (changes an artifact contract -- the recording path --
+                      and the definition of a reported metric)
+chaos            d8 = 7  → no override
+declared tier    M
+```
+
+**Declaration 4 of chaos window 3.**
+
+## The report
+
+Reviewing the maintainer's six trial notes, `make trials` said
+**positions unreachable: 4, target 0 — "the recording exists but the
+position moved."**
+
+**All four were false.** A recording holds exactly one hash, the final
+state; `reachability()` asked whether the note's hash was in that file. So
+a mid-game note could never match, and a post-game note from any but the
+last game could not either.
+
+**Instance 8 of the ADR-0018 family**, with an exact sensitivity: vary
+only *when* the note was written and the answer flips deterministically,
+with nothing having moved.
+
+## The root cause was not the metric
+
+Three defects, one cause: **`play again` reused state that belongs to a
+game.**
+
+| reused | consequence |
+|---|---|
+| the recording path | **game 1's recording destroyed** — data loss |
+| the journal (never cleared) | game 2's log opened with game 1's commands |
+| the note's `after`, counted on that journal | indexed a recording without those commands |
+
+**Fixing `reachability()` alone would have turned the number green while a
+session still destroyed its own evidence.** [ADR-0019](../decisions/ADR-0019-a-game-is-the-unit.md).
+
+## Task: a game is the unit
+
+```task
+id: CB-WP-0033-T01
+status: done
+priority: high
+```
+
+**Controls:**
+- **each fix fails on its own defect**, by mutation, or it is not tested;
+- **the metric can go red** — a check reporting 0 that cannot report
+  anything else is decoration (ADR-0006 D3);
+- **old logs stay readable and are not called orphans**;
+- **the single-game invocation GameDesign §5 documents is unchanged.**
+
+**Done 2026-08-07.** All three mutation-proven:
+
+| mutation | what went red |
+|---|---|
+| `next_game` stops clearing the journal | *"game 2 opened holding game 1's commands"* |
+| notes not filtered by game | *"game 1's comment leaked into game 2's log"* |
+| driver stops re-pathing the recording | *"game 2 was never recorded separately"* |
+
+The third is the important one: it runs the **real two-game session**, so
+it covers the call site rather than the helper. The unit test proves
+`game_path` names files apart; only the integration test proves the driver
+uses it, and the driver was where the data loss lived.
+
+**Two defects were introduced and caught while writing this.**
+
+- `cfg.record` was re-derived from the *previous game's* path, so game 3
+  would have landed in `x-2-3.yaml`. Fixed by keeping the caller's base
+  untouched, **and the compounding shape is now pinned by an assertion**
+  so the fix cannot silently rot.
+- `Server::game()` was dead code, which `-D warnings` caught. Rather than
+  `#[allow]`, the driver now *asks the server* which game it is — removing
+  a second counter that could have disagreed with the one stamped on the
+  notes.
+
+**The metric now reports honestly**: 0 unreachable, 6 legacy, and it says
+what legacy means. `trials.py` gained six controls, including the two that
+were previously **impossible to pass** — a mid-game note being reachable,
+and a note from game 2 being judged against game 2's recording.
+
+## Not done here
+
+- **No hash per command in the recording** (ADR-0019 D3). A mid-game
+  position is confirmed by replaying to it, not by string search. The
+  trigger for revisiting is a reader who needs the position without a
+  replay.
+- **The six existing notes stay legacy forever.** Their positions were
+  never checkable; nothing is gained by inventing bindings for them.