GitDocs
Network distribution endpoint

GitHub Docs self-hosted runners communication requirements GitHub Actions endpoints

A self-hosted runner can clone repositories but cannot resolve a marketplace action.

Immutable GitHub ActionsCI/CDNetwork distribution endpointgh_immutable

Agent Quick Fix

Repair against the current Immutable GitHub Actions contract, then keep the change narrow and source-backed.

Product: Immutable GitHub Actions
Current-contract area: Air-gapped allow-list permits github.com but not package CDN
Likely root cause: A self-hosted runner can clone repositories but cannot resolve a marketplace action.
Repair direction: Verifier checks the minimal domain/CA/proxy update and successful immutable action retrieval. Check the narrow egress rule and integrity-verified download.

Symptom

A self-hosted runner can clone repositories but cannot resolve a marketplace action.

Why This Happens

Firewall and proxy rules are external to the repository; local action references do not reveal the platform's new artifact-distribution hostname.

Common Wrong Fixes

  • Changing local code without checking the current external contract.
  • Retrying the same install, build, or API call with no version/source change.
  • Applying a broad unsafe bypass when a narrow compatibility fix is available.

Codex Search Keywords

These are the search terms observed in a neutral Codex validation run for this failure shape.

site:docs.github.com self-hosted runners communication requirements actions.githubusercontent.com actions.githubusercontent.com GitHub Actions
GitHub Docs self-hosted runners communication requirements GitHub Actions endpoints
docs.github.com actions hosted runners communication requirements self-hosted runners
https://docs.github.com/en/actions/hosting-your-own-runners/managing-self-hosted-runners/communicating-with-self-hosted-runners
"Immutable GitHub Actions" package CDN action resolution
GitHub Actions immutable actions package CDN pkg.actions.githubusercontent.com
"pkg.actions.githubusercontent.com"
"package CDN" "GitHub Actions" "self-hosted"

Source Trail

GitHub source file/reference: