* test: add smoke repro for missing cc in runner image
Minimal smoke workflow that calls `command -v cc` and compiles a
trivial C program. Reproduces a cargo/Rust workflow failure where
`linker 'cc' not found` breaks builds under agent-ci-dev because
ghcr.io/actions/actions-runner:latest does not ship build-essential.
CI-only change (no packages/ code modified) — no changeset.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
* feat: pluggable runner image via .github/agent-ci.Dockerfile (#208)
agent-ci now discovers a user-provided Dockerfile at
.github/agent-ci.Dockerfile (or .github/agent-ci/Dockerfile for builds
with a COPY context), hashes its contents, builds it locally via
`docker build`, and uses the resulting agent-ci-runner:<hash> tag as
the default runner image. Edits trigger automatic rebuilds; identical
contents reuse the cached image.
This closes the gap where the minimal ghcr.io/actions/actions-runner
image lacks build-essential, python3, and other toolchains that
GitHub's hosted ubuntu-latest VM ships preinstalled. Workflows green
on GitHub but failing locally with `linker 'cc' not found` can now
opt into a richer image by dropping a 5-line Dockerfile into .github/.
Resolution order (highest wins):
1. per-job `container:` (unchanged)
2. AGENT_CI_RUNNER_IMAGE env var
3. .github/agent-ci/Dockerfile (directory form, supports COPY)
4. .github/agent-ci.Dockerfile (simple form, empty context)
5. ghcr.io/actions/actions-runner:latest (default)
Also adds an error-hint heuristic: when a step fails with "command not
found" for cc/gcc/make/python3/pkg-config and the user is still on the
default image, the failure summary includes a paste-ready Dockerfile
pointing at the fix. Docs at packages/cli/runner-image.md.
Dogfoods the feature by shipping .github/agent-ci.Dockerfile for this
repo, which makes smoke-cc-compiler.yml (the issue #208 reproduction)
pass end-to-end.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
* feat: announce first-run runner image build
Print a one-time stderr notice before `docker build` fires so users
understand why the first run pauses for ~60s. The message lives in
stderr so log-update can't clobber it and stays in scrollback after.
Docs updated to match.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
* docs: clarify that container: runs verbatim, no Dockerfile layering
Spell out explicitly that a job-level container: directive bypasses
.github/agent-ci.Dockerfile entirely — agent-ci does not layer the
Dockerfile on top. This preserves the "same YAML runs locally and on
GitHub" parity promise.
Also document the two recommended ways to combine a custom base
image with agent-ci's extras.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---------
Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>
Peter Pistorius