baml-action

BoundaryML/baml-action checks, format-checks, tests, and measures a BAML project in one step. It installs BAML with BoundaryML/setup-baml, then runs:

Step	Command	Fails the job when
check	baml check	the project has compiler errors
fmt	baml fmt --check	any file is not formatted
test	baml test	any test fails
codequality	baml codequality	never; it only reports

codequality needs a toolchain from 2026-10-28 or later (a nightly, until the next release) and is skipped with a warning on older ones; fmt needs one with baml fmt --check and fails without it.

Every enabled step runs even if an earlier one fails, so one run shows every problem. The job summary lists each step's result and the code quality report.

Usage

name: BAML

on:
  pull_request:
  push:
    branches: [main]

permissions:
  contents: read
  pull-requests: write # for the code quality comment

jobs:
  baml:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v5

      - uses: BoundaryML/baml-action@v1
        env:
          # Only needed if your tests call an LLM.
          OPENAI_API_KEY: ${{ secrets.OPENAI_API_KEY }}

Inputs

Input	Default	Description
toolchain	from baml.toml	Toolchain selector passed to setup-baml: an exact version, canary, or nightly.
project	.	Project directory, passed as --project-dir (--project on older toolchains).
check	true	Run baml check.
fmt	true	Run baml fmt --check.
test	true	Run baml test. A project with no tests passes with a notice.
test-profile		Test profile from baml.toml, passed as baml test --profile.
codequality	true	Run baml codequality.
comment	true	On pull requests, post a code health summary.
github-token	github.token	Token for the comment. Needs pull-requests: write.

Outputs

Output	Description
version	Resolved concrete BAML toolchain version

Code health comment

On pull requests, the action comments with a code health summary comparing the pull request to its base. The comment updates in place on each push.

Both commits are measured with the same toolchain, so a toolchain upgrade does not show up as a code change.

Pull requests from forks get a read-only token, so the action skips the comment there and leaves the comparison in the job summary. To post as a GitHub App instead of github-actions[bot], pass that app's installation token as github-token.

Several projects

Run the action once per project. Each project gets its own summary section and its own comment.

strategy:
  matrix:
    project: [services/agent, services/extractor]
steps:
  - uses: actions/checkout@v5
  - uses: BoundaryML/baml-action@v1
    with:
      project: ${{ matrix.project }}

Contributing

This repository is a read-only mirror. Open changes against packaging/github-actions/baml-action in BoundaryML/baml.