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Instead of writing shell scripts to install tools, you can reference GitHub Actions directly in your blueprint’s initialize or maintenance sections. Devin downloads and runs the action during the snapshot build, the same way GitHub’s CI runners execute action steps. This is especially useful for language setup actions like setup-python, setup-node, and setup-go, which handle version management and PATH configuration automatically.

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Syntax

Add a uses step to any section of your blueprint: 
initialize:
  - name: Install Python 3.12
    uses: github.com/actions/setup-python@v5
    with:
      python-version: "3.12"
FieldTypeDescription
namestring (optional)Human-readable label shown in build logs
usesstringGitHub Action reference (see format below)
withmap (optional)Input parameters passed to the action
envmap (optional)Extra environment variables for the step
A step must specify either run (a shell command) or uses (an action), not both.

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Action reference format

github.com/<owner>/<repo>@<ref>
github.com/<owner>/<repo>/<subpath>@<ref>
The github.com/ prefix and @<ref> suffix are both required. The ref is typically a version tag like v5. Examples:
ReferenceWhat it resolves to
github.com/actions/setup-python@v5actions/setup-python at tag v5
github.com/actions/setup-node@v4actions/setup-node at tag v4
github.com/gradle/actions/setup-gradle@v4gradle/actions repo, setup-gradle subdirectory, tag v4

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Passing inputs

Use the with field to pass inputs to the action. All values are treated as strings, matching GitHub Actions behavior: 
initialize:
  - uses: github.com/actions/setup-java@v4
    with:
      java-version: "21"
      distribution: "temurin"
Always quote version numbers in with values. YAML interprets bare 3.10 as the float 3.1, which is not what you want. Write python-version: "3.10" instead.

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Setting environment variables

Use the env field to set environment variables scoped to a single action step: 
initialize:
  - uses: github.com/actions/setup-node@v4
    with:
      node-version: "20"
    env:
      RUNNER_DEBUG: "1"
Environment variables set by an action (via GITHUB_ENV or GITHUB_PATH) are automatically propagated to subsequent steps in the blueprint.

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Examples

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Python project with a specific version

initialize:
  - name: Install Python 3.12
    uses: github.com/actions/setup-python@v5
    with:
      python-version: "3.12"

maintenance: |
  pip install -r requirements.txt

knowledge:
  - name: test
    contents: pytest

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Multi-language project

initialize:
  - name: Install Node.js
    uses: github.com/actions/setup-node@v4
    with:
      node-version: "20"
  - name: Install Python
    uses: github.com/actions/setup-python@v5
    with:
      python-version: "3.12"
  - name: Install Go
    uses: github.com/actions/setup-go@v5
    with:
      go-version: "1.22"

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Mixing actions with shell commands

Actions and shell commands can be freely mixed in the same section: 
initialize:
  - name: Install Python
    uses: github.com/actions/setup-python@v5
    with:
      python-version: "3.12"
  - name: Install project tools
    run: pip install ruff pytest
  - name: Install Node.js
    uses: github.com/actions/setup-node@v4
    with:
      node-version: "20"
  - name: Install frontend deps
    run: npm install -g pnpm

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Java project with Gradle

initialize:
  - name: Install JDK 21
    uses: github.com/actions/setup-java@v4
    with:
      java-version: "21"
      distribution: "temurin"
  - name: Install Gradle
    uses: github.com/gradle/actions/setup-gradle@v4

maintenance: |
  ./gradlew dependencies

knowledge:
  - name: build
    contents: ./gradlew build
  - name: test
    contents: ./gradlew test

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Actions vs. shell scripts

You don’t have to use actions — plain shell commands work fine. Actions are a convenience when the equivalent shell script would be long or error-prone. 
initialize:
  - uses: github.com/actions/setup-go@v5
    with:
      go-version: "1.23"

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How it works

When Devin encounters a uses step during a snapshot build:
  1. Downloads the action repository (shallow clone at the pinned ref)
  2. Reads the action’s action.yml metadata to determine the runtime and entry points
  3. Builds the execution environment with INPUT_*, GITHUB_*, and RUNNER_* variables
  4. Runs the action’s pre step (if defined) then the main entry point
  5. Propagates side effects — any entries written to GITHUB_PATH or GITHUB_ENV by the action are applied to subsequent blueprint steps
Actions run outside of a real GitHub workflow. Context variables like github.repository are populated with stub values. Actions that require live GitHub API access (e.g., commenting on PRs, creating releases) will not work in blueprints.

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Limitations

  • Node.js actions only — Only GitHub Actions that use a Node.js runtime (node16, node20, node24) are supported. Docker-based and composite actions are not supported.
  • No post lifecycle — Devin runs pre and main steps but skips post cleanup steps, since builds run in disposable VMs.
  • Stub GitHub context — Actions that rely on GitHub API calls, workflow event data, or repository context may not work correctly because these values are placeholders in the build environment.
  • Pin your versions — Always reference a specific version tag (e.g., @v5) rather than a branch name for reproducible builds.