clay-borg/workplans/CB-WP-0042-h2-scoped-problem-stress.md

---
id: CB-WP-0042
kind: product
title: "H2 — scoped problem stress"
status: done
state_hub_workstream_id: "8f11d55b-3452-49f3-9857-d0bf06752f68"
---

# Purpose

```
structural tier  M   (touches a canonical interface: edition loading
                      becomes variant-parameterised, and the kernel gains
                      per-Problem state)
chaos            d8 = 4  → no override
declared tier    M
```

**Declaration 2 of chaos window 4.**

## Why, and it is a direct answer to ours

We reported that H1-A behaves as a **solve-rate tax**: a flat +1 to every
seat while any Problem is unclaimed, so the pressure scales with the
number of Problems while the intended effect does not.

`ground-game` responded with **H2 — scoped problem stress**. Unclaimed
Problems now tick **only the seats in their scope**:

| scope | who takes the +1 |
|---|---|
| `global` | all seats |
| `personal` | the Problem's **owner** |
| `bond` | the owner's **Bond network** — owner plus every seat reachable over Bond edges only, never Rivalry; degree 0 falls back to personal |

Assigned by hidden priority: **0 (Surface) global, 1 personal, 2 personal,
3 bond, 4 personal** — which is a seat-band dial without a difficulty
card, since 2p never has the bond card in play.

**It does not stack with H1.** `replaces_experiments: [h1-problem-stress]`,
base is `ground-darvo-r0`, and there is **no ATTACK self-soothe**.

## Why this is bigger than H1 was

H1 was two arithmetic deltas on existing state. H2 needs three things we
do not have:

1. **Variant-scoped edition data.** H2 overrides `Problems.csv` with a
   new `stress_scope` column. `edition.rs` `include_str!`s r0's copy at
   compile time — **the data is currently a constant, not a parameter.**
2. **Per-Problem ownership**, assigned at setup. That is **new state**,
   so it reaches the state hash and every recording.
3. **Bond-network reachability** — a graph traversal over Bond edges
   only, with a degree-0 fallback.

## Task: variant-scoped edition data

```task
id: CB-WP-0042-T01
status: done
priority: high
state_hub_task_id: "37f9bc34-05d1-4a12-9a98-6c61ab3ec23f"
```

**Controls:**
- **the baseline's data is bit-for-bit what it was**, and its state hashes
  do not move — the control that protected CB-WP-0038 and the one that
  invalidates every prior measurement if it fails;
- the H2 package is **vendored with digests** like every other borrowed
  file, and `edition-check` covers it — sibling discovery walks the disk
  now, so an undigested file fails (CB-REV-0003 #8);
- **`stress_scope`'s assignment is read from the file, not hardcoded.**
  The delta states the priority→scope mapping; **it is the edition's to
  state and ours to read**, and F25 exists because we hardcoded numbers
  the edition already carried.

**Done 2026-08-08.** Package vendored with digests; `edition-check` walks
it. `StressScope` and `stress_scopes()` read the column.

**H2's `Problems.csv` is r0's with one column added and nothing else
changed** — same rows, values, suits, visibilities and priorities. That is
**checked, not assumed**: the delta claims `deal_and_thresholds` unchanged,
and a silent difference would make every H2-vs-baseline comparison a
comparison of two boards as well as two rule sets.

## Task: ownership at setup

```task
id: CB-WP-0042-T02
status: done
priority: high
state_hub_task_id: "65b9b2b8-8160-488f-8cd4-b7f734d03b22"
```

`H2-OWN`: ascending hidden priority among in-play non-global Problems,
starting at Lead, stepping clockwise. Global Problems have no owner.

**Controls:**
- **deterministic**, and asserted so — the delta says "deterministic for
  sims" and a seeded-but-unstated order would be untestable;
- **the baseline carries no owners and its hash does not move.** New
  state that is `None` under baseline must serialise as it did before, or
  every recorded scenario breaks;
- **exactly one owner per eligible Problem**, checked at every seat count,
  because the assignment walks two sequences at once and off-by-one is
  the obvious failure.

**Done 2026-08-08.** `owner` and `scope` on `ProblemState`, both
`Option`, both `skip_serializing_if = "Option::is_none"` — so a baseline
state serialises **without them** and every recorded scenario's hash is
untouched. Asserted directly, on the JSON.

**`with_variant()` replaces the bare field write.** `state.variant = v`
would leave owners unassigned — **a silently wrong game rather than a
failing one** — so the builder applies the variant's setup and every
driver path goes through it.

## Task: scoped pressure

```task
id: CB-WP-0042-T03
status: done
priority: high
state_hub_task_id: "8426e79c-579e-4aba-a695-381020016206"
```

`H2-A`, at Round End, before the clamp and the DARVO arm check — the same
ordering H1-A needed, and the same trap.

**Controls:**
- **each scope fails on its own**, by mutation: global hitting only the
  owner, personal hitting everyone, bond stopping at the owner;
- **`stacking: true` is tested** — two open bond Problems must tick the
  network **twice**, and a careless implementation applies it once;
- **Rivalry edges are not traversed.** The delta says Bond only, and a
  traversal that follows any relation is the single most likely defect;
- **degree 0 falls back to personal**, which is the branch a test forgets;
- ordering asserted as in CB-WP-0038: pressure before the arm check.

**Done 2026-08-08.** All four named defects mutation-proven:

| mutation | caught by |
|---|---|
| traverse Rivalry edges too | `h2_bond_scope_does_not_traverse_rivalry` |
| stacking applied once | `h2_pressure_stacks_per_problem` |
| degree-0 owner ticks everyone | `h2_a_bond_problem_with_no_bonds_is_personal` |
| personal hits everyone | `h2_pressure_reaches_only_the_scope` |

**The degree-0 mutation missed first**, and that is worth recording: the
fallback lives *inside* `bond_network`, and the first mutation broke the
`None`-owner arm instead — a different branch. It stayed green until the
mutation was aimed at the path the test actually exercises. **A mutation
that misses is not evidence the test works.**

## Task: SOLVE is not restricted by scope

```task
id: CB-WP-0042-T04
status: done
priority: medium
state_hub_task_id: "6606cb3b-733d-486c-9e46-37a2a2b0c2c9"
```

`H2-SOLVE`: any seat with a matching suit may claim; the owner need not be
the solver, and altruistic clearing is **intended**.

**Control:** our engine has no owner concept today, so this is already
true — which makes it a **regression test, not a feature**. T02 adds
ownership, and the risk is that ownership silently becomes a permission.
The test must fail if it does.

**Done 2026-08-08**, and it does: filtering SOLVE to the owner in
`legal_commands` turns it red.

## Task: measure, and report what fails

```task
id: CB-WP-0042-T05
status: done
priority: high
state_hub_task_id: "0bcd97da-60b8-46b2-ae86-7a94f6af8dd5"
```

Same instrument as H1, same panel, both variants in one run.

**Controls:**
- **greedy and `reactive` both**, because H1's whole verdict turned on
  which policy was asked (CB-EV-0031);
- **report against ground-game's own criteria** for H2, from their design
  note — **read it, do not reuse H1's §3.2 from memory**;
- **the bond-scope hypothesis is the interesting one and must be measured
  directly**: their claim is that a shared tick makes a Bond network
  *jointly motivated* to solve that card. Whether a policy that does not
  model other seats can express that at all is an open question, and the
  honest answer may be "our panel cannot test this hypothesis";
- **`make panels` runs it**, or the figures come from an ungated binary
  again (CB-REV-0002 #7).

**Done 2026-08-08.**
[CB-EV-0032](../evidence/CB-EV-0032-h2-measured.md). **H2 largely
succeeds where H1 failed.**

| # | their criterion | verdict |
|---|---|---|
| 1 | greedy SHARED 3–4p above H1's 0 | **met** — 120 and 175 against H1's 0 and 0 |
| 2 | variance above baseline and H1-greedy | **met at 2p/4p/6p, missed at 3p** (1.50 vs 1.57) |
| 3 | DARVO for a policy that still sometimes wins | **met** — H1's clearest failure, now 13/13/57 wins with arms |
| 4 | bond SOLVE rate above personal | **not met, and untestable here** |
| 5 | control: all scopes global → collapse | **met decisively** — 120→0 and 175→0 |

**Criterion 5 is the best evidence in the pass.** Forcing every scope to
`global` and changing nothing else reproduces H1's collapse exactly, which
says the **scoping** is what saves it rather than any other difference
between the packages.

**Criterion 2's mechanism is visible in the numbers**: H1-greedy's spread
is **0.00** at 3p+. A flat tax on every seat creates no variance at all,
which is the clearest statement of why scoping was the right correction.

**Criterion 4 came out backwards, and the prediction held.** The workplan
said our panel might not be able to test it, because no policy here models
another seat or knows what a scope is. Bond claim rates are **lower** than
personal at 3p and 4p — driven by suit availability, not by incentive.
**Reported as untested with an incidental figure pointing the wrong way**,
not as a refutation.

## Not in this workplan

- **No stacking with H1.** The package forbids it explicitly.
- **No felt-play.** H2's central claim is about *motivation* — a bonded
  pair caring about each other's card — and 200-game aggregates measure
  dynamics, not that ([`Taxonomy.md`](../specs/Taxonomy.md) §4).