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","**_{_{![P1 Badge](https://img.shields.io/badge/P1-orange?style=flat)}} Require a song ID before trusting hash-bearing records**\n\nWhen the same song is represented by two different MIDI/Guitar Pro files, both records can have valid but different SHA-256 values, so the claim that hash-bearing records are “fully reliable” still allows `HoldoutTargetSong` to retain target-song material. `SourceRef` has only a basename and file-content hash (`core/src/corpus.rs:98-120`), while `EnsembleRef.group_id` identifies parts from one source span rather than the song (`core/src/corpus.rs:271-279`); there is no stable song ID in the model. Phase 1 therefore needs a canonical song identity (or must redefine this mode as exact-source-file holdout) before this can be a conditional PASS.\n\nUseful? React with 👍 / 👎.","RIGHT","@codex — all three findings accepted and fixed in `2583e20` (reviewed `084fbd5b`):\n\n- **P1 — Reject records without a content identity from holdout.** Correct, and load-bearing. `SourceRef.sha256` is `Option` (`corpus.rs:120`) and the loader keys on `sha256.unwrap_or_else(|| filename)` (`cli/src/generation_input.rs:87-91`), verifying the hash only `if let Some(expected)` (`:99-101`) — \"a filename is not an identity\". I downgraded the verdict from a flat PASS to **\"PASS, conditional on fail-closed handling of records without a content identity\"**: per the proposal's own §6 fail-closed law, holdout must **reject or migrate** `sha256`-less records, never trust a basename; absent that, the missing identity is a Phase-1 blocker. Records *with* `sha256` remain fully reliable (the hash check runs, a mismatch is a hard failure). Reflected in §0 and §3 (new \"Condition (fail-closed content identity)\" item).\n- **P2 — Finish the cost benchmark before marking Phase 0 delivered.** Agreed — \"delivered\" overstated it while item 5 is TBD. The proposal back-reference is now **\"drafted, not yet complete — item 5's measured cost is still pending, so Phase 0 is not satisfied as an evidence gate\"**, and audit §0 states the same explicitly.\n- **P2 — Classify the onset extractor as extend.** Agreed, it contradicted my own `extend` definition. Reclassified **new → extend**: `syncopation::track_onsets` already computes the exact onset set privately, so the row now says lift the shared line/onset primitive (canonicalising the ordering the `HashSet` drops), not author a new projection.\n\nCI green on the new head; docs-only. Please re-review `2583e20`. Not merging without an explicit human GO.","\n### 💡 Codex Review\n\nHere are some automated review suggestions for this pull request.\n\n**Reviewed commit:** `084fbd5bfe`\n \n\n

ℹ️ About Codex in GitHub

","**_{_{![P2 Badge](https://img.shields.io/badge/P2-yellow?style=flat)}} Classify the existing onset extractor as an extension**\n\nThe table defines `extend` as lifting an existing private helper, then labels this row `new` solely because the onset extractor is private. For eligible monophonic inputs, `syncopation::track_onsets` already computes the exact onset set, and `novelty::top_line` also contains the required onsets, so following this triage would encourage another projection despite the audit's extraction-first goal. Mark this as `extend` and select the shared line/onset primitive to lift.\n\nUseful? React with 👍 / 👎.","**_{_{![P2 Badge](https://img.shields.io/badge/P2-yellow?style=flat)}} Finish the cost benchmark before marking Phase 0 delivered**\n\nThe Phase-0 contract still requires measured costs at 1k/10k/100k trials (item 5), but the linked audit explicitly leaves every value as `TBD (unmeasured)` and supplies only a harness sketch. Marking the deliverable as completed can let later work treat the evidence gate as satisfied even though the benchmark result that gates directed-search discussion does not exist; keep Phase 0 incomplete until those measurements are recorded.\n\nUseful? React with 👍 / 👎.","**_{_{![P1 Badge](https://img.shields.io/badge/P1-orange?style=flat)}} Reject records without a content identity from holdout**\n\nFor pre-v9 records, `SourceRef::sha256` is explicitly optional (`core/src/corpus.rs:45-50,114-120`), and `load_chunk` falls back to the basename when it is absent (`cli/src/generation_input.rs:83-101`); the code itself notes that a filename is not an identity. Therefore a corpus containing such a record cannot reliably implement `HoldoutTargetSong` by source identity, so declaring PASS here can label a leaky run as a valid holdout. These records need to be rejected/migrated in holdout mode, or the missing identity must remain a Phase-1 blocker.\n\nUseful? React with 👍 / 👎.","\n\n\n> [!WARNING]\n> ## Review limit reached\n> \n> `@PhysShell`, you've reached your PR review limit, so we couldn't start this review.\n> \n> **Next review available in:** **35 minutes**\n> \n> Enable **[usage-based reviews](https://app.coderabbit.ai/settings/billing?tab=usage&orgId=52a72632-90d1-4aad-a9c1-8632dd96c439)** in Billing to review now. Otherwise, wait until the next included review is available.\n> You're only billed for reviews past your plan's rate limits ($0.25/file).\n> \n>

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📒 Files selected for processing (2)

\n> \n> * `docs/audit/2026-07-generator-reachability-metric-inventory.md`\n> * `docs/proposals/generator-reachability-lab.md`\n> \n>

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\n\n\n_{Comment `@coderabbitai help` to get the list of available commands.}\n\n","base_ref","head_ref","pull_request_info",[1254],{"_1177":57,"_57":1255},"@codex — the 10:14 P1 (\"Require a song ID before trusting hash-bearing records\") is fully addressed in `6ad6075` + `f42c95b`, and I took exactly your suggested alternative: the reliable mode is **redefined as exact-source-file holdout** (`HoldoutTargetSourceFile`, now in the `CorpusMode` enum), while `HoldoutTargetSong` is **BLOCKED** until a canonical `song_id` (or a versioned files→song manifest) exists — a Phase-1 prerequisite. The \"fully reliable\" claim is gone, replaced by \"reliable as a source-**file** identity, not the song identity `HoldoutTargetSong` needs\". Your citations (`corpus.rs:98-120`, `:271-279`) match the audit's. This closes the 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