🟡 The PR description says this change points CONFORMANCE_PKG back at the registry spec and drops CONFORMANCE_PKG_SHA256 plus the fetch-and-verify steps, but the head commit (40328e7) deliberately reversed that plan — the final diff keeps the sha256 byte-pin and both fetch-and-verify steps, pointing CONFORMANCE_PKG at the registry tarball URL instead. A squash-merge message derived from the description would misstate the supply-chain posture (implying npm's weaker integrity check applies when a byte-level pin is actually in force). The workflow code itself is correct (the pinned digest matches the published alpha.10 tarball); only the PR description needs updating.

What the description claims vs. what the diff does: The PR description's bullet list says the change will "point CONFORMANCE_PKG back at the registry spec" and "drop CONFORMANCE_PKG_SHA256 and the fetch-and-verify steps that existed only to pin the tarball bytes (as the comment they came with prescribed)". The final diff does neither: CONFORMANCE_PKG is set to the registry tarball URL (https://registry.npmjs.org/@modelcontextprotocol/conformance/-/conformance-0.2.0-alpha.10.tgz), not a bare version spec, and CONFORMANCE_PKG_SHA256 plus both jobs' "Fetch and verify conformance harness" steps are retained as the core pinning mechanism.\n\nHow the mismatch arose: The PR consists of two commits. The first, 3774e8d ("ci: repin conformance harness to published 0.2.0-alpha.10"), matched the description exactly — it switched to the bare @modelcontextprotocol/conformance@0.2.0-alpha.10 registry spec and removed the sha256 pin and fetch-and-verify steps, following the instruction the old comment prescribed. The head commit 40328e7 ("ci: pin conformance harness by tarball URL + sha256, not version spec"), authored after the PR was opened, deliberately reversed that decision; its commit message explains: "Registry version specs and dist-tags are movable, so keep the fetch-and-verify machinery from the previous pin and point it at the published 0.2.0-alpha.10 registry tarball with its digest." The description was never updated to reflect the changed approach.\n\nStep-by-step proof:\n1. PR opened 2026-07-27T13:12Z with head 3774e8d; the description's bullets accurately describe that commit (registry spec, pin dropped).\n2. Commit 40328e7 pushed afterwards (14:39 +0100) reverses the approach: the new env comment block in .github/workflows/conformance.yml (lines 17–26) reads "Pinned to the published release tarball by registry URL, with CONFORMANCE_PKG_SHA256 pinning the bytes (registry version specs and dist-tags are movable; the digest is not)".\n3. The final cumulative diff therefore keeps CONFORMANCE_PKG_SHA256 (new value fd3795fd…) and both fetch-and-verify steps — directly contradicting the description's "drop" bullet.\n4. Downloading the alpha.10 tarball from the registry and hashing it confirms the pinned digest fd3795fd3f55ee7c3395710282c3f9739ec8bffe98898bd36eca0c142e2a4234 matches exactly — the code is correct.\n\nWhy it matters: The contradiction is on a security-relevant point. A reader of the description — or of a squash-merge commit message derived from it, which is the common merge mode — would conclude the byte-level pin was removed and that only npm's weaker registry integrity check now applies. In fact the opposite is true: the byte-level pin is the retained, load-bearing mechanism, chosen precisely because registry version specs are movable. Future maintainers auditing the supply-chain posture from git history would be misled.\n\nWhy nothing else prevents this: Nothing in CI validates the PR description against the diff, and a squash merge will propagate the stale text verbatim into the commit message unless it is edited at merge time.\n\nFix: Update the PR description to match the final approach — e.g. replace the two stale bullets with: "point CONFORMANCE_PKG at the published alpha.10 registry tarball URL, keeping CONFORMANCE_PKG_SHA256 and the fetch-and-verify steps as the byte-level pin (registry version specs and dist-tags are movable; the digest is not)". No code change is needed; all six CI legs pass against the pinned tarball as-is. Nit severity: description accuracy only — nothing breaks if merged as-is.