Sprint fast CI

During a short integration sprint, pull requests and merge groups can skip the slowest proof families and leave them to the push to main that follows each merge.

Turn it on#

gh variable set SPRINT_FAST_CI --body true --repo burin-labs/harn

While the variable is exactly true, pull requests and merge groups skip:

• the Windows cross-compile check,
• the macOS deny-warnings build and lint,
• Harn conformance and the Harn source, documentation, and script audits,
• the Linux sandbox tests.

CI status accepts those skips and nothing else. A failed or cancelled job, or a skip of any other required proof, still fails it. Each run shows a Sprint fast CI notice naming what was skipped.

Pushes to main ignore the variable and run and require every proof, so a regression the sprint skipped turns main red on the merge that introduced it.

Turn it off#

gh variable delete SPRINT_FAST_CI --repo burin-labs/harn

Any value other than exactly true has the same effect. No code change is needed in either direction.

What it does not do#

• A merge group run in sprint mode is not a release proof. The release gate reuses a merge-group proof only when every proof job succeeded, so it runs the skipped lanes itself.
• Sprint runs do not count toward the merge-queue latency measurement, which admits only runs where every measured job succeeded.

check-ci-cache-policy enforces this shape: the changes job is the only reader of the variable, each skipped family gates on its decision, and CI status excuses only those skips.