---
id: CB-WP-0021
kind: product
title: "Import the edition: the game plays its own data"
status: ready
---

# Purpose

```
structural tier  M   (adds or refuses an external dependency, and changes
                      how a game is set up — a canonical interface)
chaos            d8 = 7  → no override
declared tier    M
```

Declaration 4 of chaos window 2.

## The engine has been playing a stand-in

`games/ground/src/lib.rs` builds Problems with `value: priority` and suits
cycled by index. `editions/ground-darvo-r0/Problems.csv` has carried the
real thing since 2026-07-31, and **GROUND-WP-0002 T01 ruled it
authoritative on 2026-08-03**:

| | problems/scenario | values | total | suits |
|---|---:|---|---:|---|
| `Problems.csv` | **5** | 2, 2, 2, 3, 3 | **12** | `required_solution` per problem |
| the stand-in | 3 | 1, 2, 3 | **6** | cycled by index |

GR-E01's thresholds are 2p → 5, 3–4p → 7, 5–6p → 9. **Ordinary against 12,
unreachable against 6** — which is why the maintainer's last game ended
`0` scores and `winners nobody`, and why clay-borg has been carrying
`GR-E01 unreachable below 5 seats` as a rules gap for ground-game to rule
on. It was never a rules gap.

## The constraint, measured before declaring

**AM-4a has 3,798 lines of headroom.** A CSV crate costs, marginally
against the shipped graph:

| crate | lines |
|---|---:|
| `csv` | 14,291 |
| `csv-core` | 3,360 |
| `ryu` | 3,962 |
| **marginal total** | **21,613** |

**5.7× the available headroom.** `itoa`, `memchr`, `serde` and
`serde_core` are already present and cost nothing; the parser itself is
what does not fit.

So the shipped runtime cannot gain a CSV parser, and that is settled by
measurement rather than by preference. What remains is *which* of the
alternatives to take, and that is the ADR.

## Task: decide how the data reaches the game

```task
id: CB-WP-0021-T01
status: todo
priority: high
```

Write `decisions/ADR-0011-*.md` (tier M: survey and decision in one).

**Three questions, and the third is the one that bites.**

**(a) Where does the data live?** `ground-game` is a separate repository.
Depending on a sibling checkout makes the build depend on a path that may
not exist; vendoring a copy makes clay-borg carry content it does not own.
Whichever is chosen must say how a copy is known to be current, because a
silently stale copy is worse than no copy.

**(b) How is it parsed, given a CSV parser does not fit?** Candidates, and
each needs its marginal cost stated rather than assumed:
  - hand-rolled reader in `games/ground` — small, but it is a parser we
    then own, and `problem_text` contains commas;
  - **bake it**: a dev-time step converts the CSV into a generated Rust
    module or compact literal, so the shipped runtime parses **nothing**.
    Then the generated artifact must be proven to match its source, which
    is the DFD class this repo already has machinery for;
  - load nothing at runtime and treat the data as scenario input.

**(c) What does this do to determinism?** Problem values and required
suits become part of `GroundState`, which is hashed (K7). **Every recorded
state hash changes.** Before writing code, establish what actually pins a
hash today — `make sim` runs 25 scenarios, `replay-test` re-executes
bundles, and AM-7's probe asserts per-segment hashes. Say which of those
break, and whether any of them are *supposed* to be stable across a
content change.

**This is the reason the ADR exists.** A content import that quietly
invalidates every recorded hash, in a project whose central invariant is
replay determinism, is not a data-loading change.

## Task: import it, and let the thresholds mean something

```task
id: CB-WP-0021-T02
status: todo
priority: high
```

Replace the stand-in. `setup` must build Problems from the edition data:
`point_value`, `required_solution`, `visibility` (Surface → face up,
Hidden → face down) and `hidden_priority`.

**Controls:**
- **The stand-in must become unreachable.** A test that the fixture
  constants no longer appear — a `value: priority` that survives beside
  real data is a fallback nobody will notice until the numbers look odd
  again.
- **A scenario must be able to reach GR-E01's threshold at 2 players**,
  which is the specific thing that was impossible. Assert the arithmetic,
  not just that a game runs.
- The 5-problem shape must survive: the stand-in dealt 3, and code that
  assumed 3 will not announce itself.

## Task: retire the rules gap that was never one

```task
id: CB-WP-0021-T03
status: todo
priority: medium
```

`gr-e01-threshold-unreachable-2p` is tagged `provisional: true` with
`provisional_owner: ground-game`, and its description says group success
*"is unreachable at 2, 3 and 4 players"*. If T02 lands, that scenario is
asserting a property of the **stand-in**, not of the game.

Retire or rewrite it, and **say which of the six provisional items this
resolves**, so GROUND-WP-0002 T03 shrinks rather than being left to
rediscover it. Message `ground-game` with the outcome — the last such
message sat unread for four days because nothing pointed at it.

Do **not** quietly delete a failing-in-fact scenario. CB-EV-0005: *a score
improved by deleting the question is not an improvement.*

## Task: evidence

```task
id: CB-WP-0021-T04
status: todo
priority: high
```

`evidence/CB-EV-0019-*.md`.

- **What the import cost**, against the 3,798 lines that were available.
- **What broke**, especially hashes, and whether the blast radius was
  predicted in T01 or discovered in T02. If it was discovered, say so —
  that is the ADR having missed something.
- **Whether the endings now mean anything**: play one and report the
  score against the threshold.
- **Quote CB-WP-0020's cost by re-running the instrument.**
- **Chaos: 4 of 12 in window 2.**