Run Claude Code in a Container

This page describes action: harness.run with provider: claude inside a Docker or Podman container.

The examples use an image named dagu-claude-runner:local. Build that image before running the DAG examples.

Requirements

• The Dagu process can reach Docker or Podman.
• The runner image contains claude in PATH.
• The container can reach the network for real claude -p runs.
• Authentication is provided with ANTHROPIC_API_KEY, ANTHROPIC_AUTH_TOKEN, CLAUDE_CODE_OAUTH_TOKEN, cloud-provider environment variables, or a mounted Claude Code credentials directory.

Claude Code's current installation and authentication behavior is documented by Anthropic:

• Claude Code setup
• Claude Code authentication

Build the Runner Image

Claude Code can be installed as a global npm package. The package requires Node.js 18 or later.

FROM node:22-bookworm-slim

RUN apt-get update \
  && apt-get install -y --no-install-recommends \
    ca-certificates \
    git \
    ripgrep \
    bash \
  && rm -rf /var/lib/apt/lists/*

RUN npm install -g @anthropic-ai/claude-code
RUN claude --version

WORKDIR /workspace
ENTRYPOINT []
CMD ["bash"]

Build and verify the image:

docker build -t dagu-claude-runner:local -f Dockerfile .
docker run --rm dagu-claude-runner:local claude --version

Verify the Image Through Dagu

This DAG starts a container and calls claude --version. It does not make a model request.

harnesses:
  shell:
    binary: sh
    prefix_args:
      - -c
    prompt_mode: arg

steps:
  - id: claude_version
    action: harness.run
    container:
      image: dagu-claude-runner:local
      pull_policy: never
    with:
      provider: shell
      prompt: |
        set -eu
        claude --version
        command -v claude

The command must print the Claude Code version and the path to the claude binary.

Step-Level Container

Use a step-level container when only the Claude Code step should receive the workspace mount and credential.

env:
  - ANTHROPIC_API_KEY: ${ANTHROPIC_API_KEY}

steps:
  - id: review
    action: harness.run
    container:
      image: dagu-claude-runner:local
      pull_policy: never
      working_dir: /workspace
      volumes:
        - .:/workspace:ro
      env:
        - ANTHROPIC_API_KEY=${env.ANTHROPIC_API_KEY}
    with:
      provider: claude
      prompt: |
        Review this repository and summarize the highest-risk issues.
      model: sonnet

provider: claude invokes claude -p "<prompt>". In non-interactive mode, Claude Code uses ANTHROPIC_API_KEY when that variable is present.

Root-Level Container

Use root-level container: when ordinary command steps and Claude Code should share the same container filesystem and toolchain.

container:
  image: dagu-claude-runner:local
  pull_policy: never
  working_dir: /workspace
  volumes:
    - .:/workspace

harnesses:
  shell:
    binary: sh
    prefix_args:
      - -c
    prompt_mode: arg

steps:
  - id: test
    run: npm test

  - id: claude_tools
    action: harness.run
    with:
      provider: shell
      prompt: |
        set -eu
        claude --version
        command -v claude

This example verifies the shared container path without making a model request. For a real Claude Code step, replace the shell provider with provider: claude and pass authentication.

If the root-level container receives an Anthropic key, bearer token, OAuth token, or mounted Claude credentials, every inherited step in that shared container can read it.

Authentication

Claude Code chooses credentials in the order documented by Anthropic. For Dagu container runs, the credential must be available inside the container.

API Key

env:
  - ANTHROPIC_API_KEY=${env.ANTHROPIC_API_KEY}

Bearer Token

env:
  - ANTHROPIC_AUTH_TOKEN=${env.ANTHROPIC_AUTH_TOKEN}

Long-Lived OAuth Token

Generate the token on the host:

claude setup-token

Then pass it to the container:

env:
  - CLAUDE_CODE_OAUTH_TOKEN=${env.CLAUDE_CODE_OAUTH_TOKEN}

Anthropic documents that --bare does not read CLAUDE_CODE_OAUTH_TOKEN. Do not set bare: true in the Dagu step when this token is the only credential.

Mounted Credentials Directory

On Linux, Claude Code stores credentials under ~/.claude/.credentials.json unless CLAUDE_CONFIG_DIR is set. Mount the host directory and set CLAUDE_CONFIG_DIR inside the container:

steps:
  - id: review
    action: harness.run
    container:
      image: dagu-claude-runner:local
      pull_policy: never
      volumes:
        - ${HOME}/.claude:/claude-config
      env:
        - CLAUDE_CONFIG_DIR=/claude-config
    with:
      provider: claude
      prompt: |
        Review this repository.

On macOS, Claude Code stores login credentials in the macOS Keychain. A container cannot read the host Keychain by mounting ~/.claude.

In container.volumes, ${HOME} is expanded on the Dagu worker. The /claude-config target is the literal path inside the container.

Links

• Claude Code provider reference
• Harness runner images
• Harness container credentials