This is pipeline/tooling work only: a Europe PMC fallback for PubMed Central pages, a DOI→PMCID lookup, JATS-to-text rendering, tests, and a dated DECISIONS.md entry. No content/ records are added, and the tooling found no citation identifiers to resolve, so no fabrication surface exists in the ledger. Provenance handling is strengthened rather than weakened: the retrieved substitute is returned under the original page's key but with `substitute: true` and a `via` string naming the exact Europe PMC endpoint and PMCID ("Europe PMC full text (JATS XML) for PMC…, at …, read for the page"), and when both routes fail the two reasons are joined rather than the failure being papered over — consistent with §3.8 and with the 'blocked with the route, not read from memory' comment in the existing header. Nothing in §3.15's checks is loosened; CI, ratification, and labeling paths are untouched. AGENTS.md is not edited; DECISIONS.md is, which is permitted, and its founder-direction stamp is dated and channel-marked as §3.15 allows. The PR body's claim of a live check against PMC12647689 is unverifiable from here but is not a ledger citation and shows no internal inconsistency.

The retrieval fallback preserves the original source URL as the record key while explicitly marking substituted Europe PMC text with `substitute: true`, `via`, PMCID, DOI where applicable, and the actual full-text endpoint. It does not silently treat failed retrieval as evidence: unsuccessful direct and fallback attempts return recorded reasons, while transformed JATS is identified as such. The tests cover direct retrieval, substitution, DOI-to-PMCID matching, and joined failure reporting, and no content citations, confidence material, constitutional edits, or weakened publication checks are introduced.

The change improves pipeline retrieval robustness by falling back to Europe PMC's JATS full-text API when PMC blocks automated retrieval, and by looking up PMCIDs for walled DOIs. It scrupulously respects provenance (§3.8) by retaining the original target URL as the key while explicitly setting `substitute: true` and marking the source provenance in the `via` field so stand-in text is not mistaken for a direct scrape. AGENTS.md is untouched, test coverage is thorough, and the architectural decision is properly recorded in DECISIONS.md.

The diff is retrieval infrastructure only (fetch.ts, tests, and a DECISIONS.md log entry). It does not edit AGENTS.md, add content claims or citations, touch confidence material, or loosen §3.15 checks. Europe PMC is used as an explicit stand-in: the original page stays the key, via/substitute are set, and failed routes are joined in the reason — aligning with exact provenance and honest verification labels rather than inventing locators or silently substituting text. No run records or omitted files; citation verification found nothing added under content/.

This is a retrieval-infrastructure change (fetch.ts plus tests plus a DECISIONS.md log entry), with no content records, no citations added, and no AGENTS.md edit — the DECISIONS.md edit is the decisions log, which entries of this kind belong in. The change does not weaken the §3.15 checks; it strengthens honest retrieval by marking Europe PMC-served text with `substitute: true` and a `via` string naming the exact service, PMCID, and URL, so a quote the stand-in cannot verify is labeled unverified rather than silently counted — consistent with §3.8's requirement that unverified locators be labeled and never invented. The DOI-to-PMCID lookup cross-checks the returned record's DOI against the requested one before use, and the test fixtures' mock DOIs/PMCIDs are exercised against mocked fetch responses, not published as citations (citation verification found no identifiers in added content lines). The `Supervised-by: founder (direction in session, 2026-09-20)` stamp in the log is an unverifiable provenance claim, but nothing in the material contradicts it, and it matches the recorded-todo pattern the PR body describes; no citation, locator, or provenance detail is fabricated. If the founder direction was not in fact given in session, the log entry would need correcting, but nothing shown raises that doubt.