source-extract-fidelity

name	source-extract-fidelity
description	Independently reviews a batch of source-extract reference pages against the source binary so that no prose claims more than the committed extract supports — checking hash match, extract fidelity, and that every quoted figure traces to a committed extract with a cross-reference treated as not-a-quote and a derived number as not-quoted. Use when reviewing extracted/source-derived pages before merge, especially text-faithful pages whose prose may overreach.
license	CC-BY-4.0
compatibility	Requires the source binary (or its verified temp copy), the committed extract (txt/CSV) + sha256 pointer, and a closed status vocabulary on pages
metadata	{"version":"1.1","enforcement_level":"L2","status":"template","incident_refs":"prose-overclaim,crossref-as-quote,derived-as-quoted","params":"batch:str | round:int=1"}

source-extract-fidelity

Template skill (doc 03, doc 04). Extraction can be byte-perfect and the page still wrong — because the prose around the extract claims more than the extract supports. Across a 53-document campaign the dominant defect class was not bad extraction but prose overclaiming beyond the extract: a number that was cross-referenced (not quoted), a value that was derived (not stated), or a clause re-ordered so it no longer matches the source. This skill is the independent verify loop that catches that.

What this gates: the batch PR (a needs-verify → verified label flow), not each page's parse_status. Pages may stay parse_status: provisional even after the batch passes — per-row promotion to verified is a separate step. This skill is the independent batch review run before the PR is cleared to merge.

Trigger

/source-extract-fidelity <batch> [--round 1|2]

Preconditions

1. The reviewer is independent of the producer — a different agent/pass, prompted to find a reason the page is wrong, not to confirm it looks fine.
2. The source binary is available as a verified copy (hash matches its pointer); for off-disk LFS binaries, fetch via lfs-batch-fetch first.
3. Each source's sha256 is recorded in the page's source table and in sources/README.md, and pages use the closed status vocabulary (parse_status / trust_label / derivation_status).

Steps

1. Hash gate. Recompute the source sha256 and confirm it matches the value recorded in the page's source table / sources/README.md. A source that can't be reproduced from its recorded hash is invalid before any prose is read.
2. Extract-fidelity check. Compare the committed extract (txt/CSV) against the source: did the deterministic lane capture what it claims (right sheet/slide/ thread, no silent truncation)? Note any known-lossy gap (see format-coverage-ledger) but do not penalize a faithful extract for the text/CSV lane's known loss.
3. Quote traceability — the core check. For every quoted figure, name, or clause on the page, find the exact span in the committed extract. Apply the closed rules:
   • A cross-reference ("per the calc in sheet X") is NOT a quote — it must not be rendered as if the value were stated here.
   • A derived number (computed/rounded/unit-converted from extract values) is NOT "quoted" — it is derivation_status: derived, never a verbatim capture.
   • A quote must match clause order exactly. Re-ordering clauses to read better changes meaning; a re-ordered quote is a defect, not a paraphrase.
4. Overclaim sweep. Read every declarative sentence and ask: does the committed extract contain this? Anything beyond the extract (interpretation, conclusion, "this means…") must be labeled output/analysis, never presented as source. Unsupported source-claims → flag for correction. For ACE wave-1 config/code-doc rows, claims must trace to the retained metadata, docstring, comment, or schema key. Generated JSON exclusions must not be converted into prose claims about source content.
5. Invariant + vocab check. Confirm raw binary is not committed (only derived parts + pointer), private content hasn't crossed to public, and every status value is in the closed set (no invented labels).
6. Verdict + further rounds until PASS. Emit a per-page verdict with cited defects. Each later round re-checks what the producer corrected, again adversarially — a "fixed" page often just moved the overclaim, and a code fix can be narrower than the defect class. Two rounds is the floor, not the ceiling: the loop ends at a clean PASS, never at a round count (GP-42; one campaign fix needed a third round, caught by a reviewer-built reproducer — see adversarial-verify-loop).

Verification

• Every quoted span on every page resolves to an exact location in the committed extract (the traceability map is complete — no orphan quotes).
• No derived/cross-referenced value is presented as a verbatim quote.
• Config-derived and code-doc claims trace to retained metadata/docstrings; no prose claim is inferred from excluded generated JSON.
• Hash matches; invariants and closed-set vocab hold.
• Defects cite a specific falsifiable location ("page says X, extract has Y"), not generic approval/disapproval.

Cleanup

• n/a (read-only review). The fetched source temp copy is removed by the fetch skill's cleanup.

Incident appendix

Rule	Why
Independent, adversarial reviewer	Charitable self-review rubber-stamps; the producer can't see its own overclaim
Quote must trace to a committed extract	The #1 defect class: prose claiming more than the extract supports
Cross-reference ≠ quote	A pointer to where a value lives is not the value being stated here
Derived number ≠ quoted	Computed/converted values are derived, never verbatim captures
Clause order must match	Re-ordering a quote silently changes its meaning
Cite a falsifiable defect	When two reviews disagree, the specific-location claim wins over generic approval
Verify until PASS, not for N rounds	A fix can address the cited example but not the invariant; the round that catches it is the loop working