A prefetch state reader, a pinned upstream ref and a freshness check are compiled in and never called.
What
The runner gained machinery to reuse an already-fetched copy of a repository instead of cloning it: a reader for a prefetch state file, a pinned upstream ref refs/remotes/prefetch/staging, and a function to judge whether the prefetch is fresh enough to trust. None of it runs. Every clone still does a full fetch.
Details
- The reader is called on the clone path but its body returns immediately, so the prefetched tip is never populated.
- The eligibility function, the only thing that would weigh freshness, repo identity, worktree mode and worker epoch, has no caller anywhere in the build.
- The git prepare function accepts the new prefetched-tip argument and never reads it; its fetch is wrapped in a build-time-true condition, so the skip-the-fetch branch is compiled out. A sibling telemetry helper returns an empty object.
- Were it switched on, it would require the environment variable
CLAUDE_RUNNER_TRUST_CANONICAL_PREWARMset with--drain-grace-sec 0, single-worker mode, and the hardcoded repositoryanthropics/anthropic, making it an Anthropic-internal path rather than a general one.
Evidence
canonical is not a trusted one-shot prewarm (CLAUDE_RUNNER_TRUST_CANONICAL_PREWARM unset or drain-grace > 0), refs/remotes/prefetch/staging
Strings lifted out of the shipped bundle, so the claim above can be checked against them.