diff --git a/README.md b/README.md
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--- a/README.md
+++ b/README.md
@@ -264,6 +264,8 @@ python scripts/run_benchmark.py \
 
 `felix` here is a technical harness name (the original 7-agent stack), not a product.
 
+Public proof of a cell is a replayable pack: challenge file, expected judgment name, and pass/fail over printed receipts (`summary.json`, events, preflight adapters). Chain-of-thought and abridged reasoning traces do not count. Packing rules: [docs/public-proof-challenge-packs.md](docs/public-proof-challenge-packs.md). This board stays the N=1 `spread-2026-09-07` cite.
+
 | # | Harness / model | Mean | Final | vs baseline | Cost |
 |---|-----------------|------|-------|-------------|------|
 | 1 | Grok Build (ACP) / grok-4.6 | **0.811** | 0.833 | −0.021 | $7.00* |
diff --git a/docs/bench-design-n-ticks.md b/docs/bench-design-n-ticks.md
index 9fb9568..4bf9345 100644
--- a/docs/bench-design-n-ticks.md
+++ b/docs/bench-design-n-ticks.md
@@ -103,3 +103,12 @@ Val proved check-zone + work-priority schema. Gates2 proved work-priority
 repeats and tend; research rejects were **no bench / prereqs**, not a
 schema miss. Stockpile-delete and the farm already-covered branch are
 still open QA.
+
+## Public proof
+
+Replay a claim with a challenge pack: challenge file, expected judgment
+name, and pass/fail over `summary.json`, events, and preflight adapters.
+Rules and judgment names: [public-proof-challenge-packs.md](public-proof-challenge-packs.md).
+Chain-of-thought and abridged reasoning traces are not receipts. The
+figures in this memo are unchanged. The live board remains
+`spread-2026-09-07`, N=1.
diff --git a/docs/public-proof-challenge-packs.md b/docs/public-proof-challenge-packs.md
new file mode 100644
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+++ b/docs/public-proof-challenge-packs.md
@@ -0,0 +1,111 @@
+# Public-proof challenge packs
+
+A public RLE proof is three printed artifacts:
+
+1. a **challenge file** (`challenge.yaml` or `challenge.yml`)
+2. an **expected judgment name**
+3. a **pass/fail** result of a deterministic predicate over a **printed receipt**
+
+That is the whole proof. The receipt is one of `summary.json`, an events JSONL file, or a preflight-adapter JSON file. If those three artifacts are absent, the claim does not count.
+
+This memo defines the pack. It does not change scoring, the game loop, or any published board number. The live cite stays `spread-2026-09-07` (Crashlanded, 10 ticks, seed 42, N=1, scoring 1.2). That board is content-first: one observation per cell, no within-cell σ. See [bench-design-n-ticks.md](bench-design-n-ticks.md).
+
+## Chain-of-thought is not a receipt
+
+A private chain-of-thought, an abridged `reasoning_trace` / `reasoning_traces` dump, or a narrative math writeup is a story about a run. It is not an RLE proof.
+
+Predicates read receipt fields only. They do not read reasoning text. A receipt object that carries `reasoning_trace` or `reasoning_traces` fails closed: those keys are narrative, and packing them into the proof artifact does not satisfy a judgment. The same keys on an events line make that line ineligible. OpenAI-style abridged reasoning traces stay in that category.
+
+## Pack shape
+
+One directory per pack. `challenge.yaml` is the challenge. `receipts/pass/` and `receipts/fail/` hold the printed files the predicates name. Fixture packs check both directories in unit tests. A harness pack checked into the tree uses the same shape; producing the receipt still means printing `summary.json`, events, or a preflight adapter — not a transcript.
+
+```yaml
+schema_version: 1
+id: research_bench_present          # matches the directory name
+scenario: Crashlanded Survival      # scenarios/definitions name
+seed: 42                            # RLE-side seed recorded on the summary
+tick_budget: 10                     # ticks the receipt may consume
+mode: fixture                       # fixture | harness
+harness: fixture                    # harness name; "fixture" when mode is fixture
+model: fixture                      # model id; "fixture" when mode is fixture
+scoring_version: "1.2"              # SCORING_VERSION the receipt was scored under
+expected:                           # judgment names only — no prose, no rates
+  - research_bench_present
+pass_fail:
+  - judgment: research_bench_present
+    receipt: preflight.json         # file under receipts/<case>/
+    match: object                   # object (JSON) | any (JSONL line)
+    all:
+      - path: research_bench_present
+        eq: true
+      - path: structures.0.def_name
+        eq: SimpleResearchBench
+    absent:                         # top-level keys that fail the judgment
+      - reasoning_trace
+      - reasoning_traces
+```
+
+`mode: harness` uses the same fields with `harness` and `model` set to the pair that printed the receipt. Naming a pair records provenance. It does not add a leaderboard row and it does not authorize an N>1 matrix.
+
+| Field | Rule |
+|-------|------|
+| `schema_version` | `1` |
+| `id` | Directory name |
+| `scenario` | Scenario `name` from YAML. These packs use `Crashlanded Survival`. |
+| `seed` | Integer. Compared to `summary.json` `random_seed` when that judgment reads the summary. |
+| `tick_budget` | Positive integer. `ticks_run` on a summary receipt must be ≤ this budget. |
+| `mode` | `fixture` (checked-in receipts, no live game, no billed model) or `harness` (a printed run). |
+| `harness`, `model` | Both `fixture` when `mode` is `fixture`. Both non-empty and not `fixture` when `mode` is `harness`. |
+| `scoring_version` | `"1.2"` (`SCORING_VERSION` in `tracking/metadata.py`). |
+| `expected` | List of judgment names from the catalog below. |
+| `pass_fail` | One predicate per expected name. `judgment` must appear in `expected`. |
+
+## Expected names
+
+`expected` is a list of typed names. A name is the judgment. It is not a score, a rate, or a sentence.
+
+| Name | What the predicate reads |
+|------|--------------------------|
+| `research_bench_present` | Brief flag from `research_bench_present()`: true when a structure `def_name` matches `is_research_bench_def` (`SimpleResearchBench`, `HiTechResearchBench`, and the same aliases). |
+| `research_adapters` | `RimAPIClient._adapt_research` fields `current_project`, `progress`, `completed`, `available`, plus `research_target_status` (`available`, `current`, `finished`, `locked`). The failure shape is the tech-level bag the adapter refuses: `completed: ["Medieval"]`, empty `available`, status `locked`. |
+| `ensure_live_save` | `LiveSaveStatus` fields `save_name`, `live_save_sha256`, `pinned_sha256`, `copied`. Pin-match: the two hashes are equal and `error` is absent. Stale AppData that cannot be staged raises `LiveSavePinError` and fails closed (`scenarios/loader.py`). |
+| `stockpile_delete_quarantine` | `action_exec` event for `stockpile_delete`: `success` false and `error` containing `quarantined`. `QUARANTINED_WRITES` hides the endpoint; the executor refuses it before HTTP. |
+| `preflight_contract` | The five dispatch gates in `orchestration/preflight.py`: growing-zone already covered, `work_priority` normalized to a WorkTypeDef, `research_target_status`, a resolved tend pair, and `stockpile_delete` quarantined. |
+| `composite_receipt` | Per-run `summary.json` from `scripts/run_scenario.py`: `scoring_version`, `scenario`, `random_seed`, `harness`, `model`, `ticks_run`, `final_score`, `outcome`. |
+
+Names outside this catalog are not judgments. Adding a name is a doc change plus a fixture, not a new board number.
+
+## Pass/fail
+
+Each predicate names one receipt file and a list of clauses. A case passes when every clause holds. `match: object` applies clauses to one JSON object. `match: any` applies them to at least one JSONL line after `where` (a map of dotted-path equalities, usually `event_type: action_exec`).
+
+A clause has one operator:
+
+| Operator | Holds when |
+|----------|------------|
+| `eq`, `ne` | The value at `path` equals / differs. |
+| `lte`, `gte` | Numeric comparison. Booleans are not numbers. |
+| `contains`, `not_contains` | Substring, or list membership. |
+| `type` | `number`, `string`, `bool`, `list`, or `object`. |
+| `present` | Path exists and is not null. |
+| `absent` | Path is missing or null. On the predicate itself, `absent:` is a list of top-level keys. |
+| `eq_path` | Value at `path` equals the value at another dotted path (`live_save_sha256` vs `pinned_sha256`). |
+
+Paths are dotted. A numeric segment indexes a list (`structures.0.def_name`).
+
+`final_score` is checked only as a number on the summary. The predicate does not compare it to a published composite. A fixture may carry any in-range shape value; that value is not a result.
+
+## Receipts
+
+**`summary.json`** — the object `_build_run_summary` writes (`collect_metadata` plus scenario, harness, model, `ticks_run`, `outcome`, `final_score`, `live_save_sha256`, `live_save_copied`). One file is one run.
+
+**Events JSONL** — `Event` lines from `tracking/event_log.py` (`event_type`, `tick`, `data`). `action_exec` lines carry `action_type`, `success`, `error`, `parameters`.
+
+**`preflight.json`** — a printed adapter or gate receipt: the research-bench flag and structure defs, the research-adapter object, a `LiveSaveStatus` / `LiveSavePinError` record, or the preflight gate fields. It is not a model transcript.
+
+## N stays on the claim surface
+
+Per-run `summary.json` has no `n_runs` field and no pass rate. `n_runs` exists on `BaselineReference` and `BaselinePoint` (how many no-agent runs were aggregated into the pinned baseline sidecar). A `composite_receipt` predicate rejects `n_runs` and `pass_rate` on the summary so a single receipt cannot pose as a matrix cell.
+
+The published N=1 caveat is unchanged: `spread-2026-09-07` is one observation per cell. This packing spec does not size a matrix, does not report a new pass rate, and does not move the 25-tick horizon lock.