clay-borg/evidence/CB-EV-0019-import-the-edition.md

# CB-EV-0019 — import the edition

CB-WP-0021 T04. Tier M (structural M — adds or refuses an external
dependency and changes how a game is set up; chaos d8=7 → no override).
Closed 2026-08-05, four days after the code landed.

**Delivered:** [ADR-0011](../decisions/ADR-0011-vendor-the-edition.md),
`editions/ground-darvo-r0/Problems.csv` with a digest, a ~150-line reader
in `games/ground/src/edition.rs`, `tools/edition-check.py`, and the ruled
deal — Surface ∪ hidden `1..=k`.

---

## 1. What the import cost, and the budget it was measured against

**The declaration's constraint was measured against the wrong
denominator, and the ADR corrected it.** CB-WP-0021 said a CSV crate costs
21,613 lines against AM-4a's **3,798** of headroom — *"5.7× over, settled
by measurement rather than preference."*

`setup` and `problem_priorities` are `#[cfg(feature = "scenarios")]`.
**They are not in the shipped runtime**, so AM-4a never sees them. Against
AM-4b's graph:

| | lines |
|---|---:|
| AM-4b headroom | 19,742 |
| `csv` marginal (`csv` + `csv-core`; `ryu`/`itoa`/`memchr` already present) | **17,651** |

**It fits, with 2,091 to spare — and was refused anyway**, on proportion:
89% of everything the budget had left, to read 20 rows. What shipped is a
hand-rolled reader we own.

**That is the third premise this pass had to correct**, and the second
where a real number was computed against a mis-chosen denominator. The
pattern is now well enough attested to name: *this project's arithmetic
errors are not in the arithmetic.* CB-WP-0022 T02 produced two more of the
same shape four days later.

Current dependency position, `make dep-weight`:

```
AM-4c shipped-runtime   7,976 own lines per 100k third-party  (diagnostic)
AM-4c dev-toolchain     1,729 own lines per 100k third-party  (diagnostic)
```

## 2. What broke — and the hash blast radius was predicted, not discovered

The task asked which it was. **Predicted, and then measured to be almost
nothing.**

T01's brief said Problem values and suits enter `GroundState`, which is
hashed (K7), so *"every recorded state hash changes"*, and required the
blast radius be established **before writing code**. ADR-0011 §Decision 3
did exactly that:

| | |
|---|---:|
| scenario files pinning a state hash | **0** |

So the feared radius was ~0. Scenarios assert on state *blocks*, not
hashes; `replay-test` re-executes bundles and restores them; AM-7's probe
asserts per-segment hashes within a run rather than against recorded
literals.

**No hash was grandfathered and none recorded as "was"** — ADR-0011's
words: *a recorded hash that outliving the content it describes is a lie
with a timestamp.*

Verified today:

- `make replay-test` — **14/14 controls passed**, including *"the bundle
  still replays after every control restored it"*;
- `make am7` — scaling **0.985 / 0.998 / 1.018** (worst/median/best of 9)
  against a 0.9 floor. Green, after T06 fixed the *measurement* rather
  than lowering the floor.

**What did break** was the scenario corpus's data assumptions: six
scenario files needed value/suit updates (`gr-a02-solve`,
`gr-e03-common-problem`, `gr-e04-coalitions`, `gr-f02-no-gate`,
`gr-p05-solve-legality`) because they encoded stand-in numbers. That is
the expected cost of replacing invented data with real data, and every one
was a data edit rather than a logic change.

## 3. Do the endings mean anything now? Yes — and the margin is one point

This is the question the pass existed for. Played today, 2 players,
all-bots:

```
OUTCOME  total 4 / threshold 5  group failure
  personal:  P1 2  P2 2
  mastery 2
  problems:  [1] Repair 2 claimed by P2  [2] Clarify 2  [3] Boundary 2 claimed by P1
```

**Three Problems worth 2 each — 6 available against a threshold of 5.**
The bots claimed two of three, scored 4, and lost by one point.

**This confirms T02's control by play.** That control said: *"at 2p that
means a **full clear**, since 2+2+2 against 5 leaves no slack."* It is
exactly right — at two seats, leaving any single Problem unclaimed loses
the game. The endings are not merely reachable; they are **tight**, which
is a far better answer than "reachable" and was not guaranteed by the
ruling.

**And it retires the finding this pass was built around.** GR-E01 was
raised as *"unreachable below 5 seats"* on 4/6/9 against 5/7/9. The real
deal is 6/9/12 against 5/7/9. `gr-e01-threshold-unreachable-2p` is now
`gr-e01-threshold-reachable-2p`, non-provisional, and the finding was
**formally withdrawn to ground-game on 2026-08-05** (CB-WP-0022 T06) —
because it took an adversarial review, four days later, for anyone to
notice that this pass had already falsified it.

**That is the sharpest thing in this evidence file.** The work that
disproved GR-E01 is *in this workplan*. The workplan that quoted GR-E01 as
its founding example was written the next day. Nothing connected them
until a separate agent ran `git log`.

## 4. Quoting CB-WP-0020's cost — the instrument refuses

T04 asked for CB-WP-0020's cost by re-running the instrument. It cannot be
supplied:

```
$ python3 tools/cb-cost.py --slug CB-WP-0020 --by-task
ABORT — no transcripts found for CB-WP-0020
```

**The instrument aborts rather than estimating, which is correct
behaviour** and is why the number is absent instead of wrong. CB-WP-0020's
transcripts are outside the retained window.

What the instrument does report, run today:

```
main          $ 548.03      output       2,125,069 tok   $ 56.16  10.1%
subagent tree $   5.50      cache_read 750,152,134 tok   $394.44  71.3%
TOTAL         $ 553.53      write_1h     9,233,711 tok   $ 97.48  17.6%

  UNATTRIBUTED     $230.34   41.6%
  CB-WP-0021-T01   $ 17.15    3.1%   PROVISIONAL — this pass's own
  CB-WP-0021-T06   $ 14.31    2.6%   PROVISIONAL — this pass's own
```

**The two CB-WP-0021 rows are provisional and must not be quoted as
final.** They are this pass's own spend, measured while writing this file,
so the number is still moving — `loop-lint`'s `own-cost` rule caught the
first draft asserting them flat, which is the rule working.

**41.6% unattributed is the number worth carrying forward**, not any
per-task figure. A cost instrument that cannot say where two-fifths of the
spend went is a partial instrument, and the retention window is why the
chain of *"quote the previous pass's cost"* — a rule designed to keep
costs comparable across passes — **breaks after roughly four passes.**

That rule should either be bounded to what the window holds, or the window
extended. It is not this pass's to decide; it is recorded here because
this is the first pass where the chain actually snapped.

## 5. Chaos window 2

**Declaration 4 of 12.** Structural M, d8 = 7, no override. The roll is
recorded per §Loop tiers even though it changed nothing.

Window 2 standing: no override has yet changed an outcome. The retirement
condition — *retire if an override changes nothing twice running* — has
not been triggered, because there have been no overrides to evaluate.

## Open after this pass

- **The cost chain is broken** (§4) and the rule that depends on it needs a
  bound.
- The wrong-denominator pattern (§1) now has three instances and no
  control. `facts-check` catches copies that disagree; nothing catches a
  number computed correctly against the wrong base.