mancube/dagron-step-mcp repository overview

⁠dagron MCP-tool step (mancube/dagron-step-mcp)

A dagron task that calls one tool on an MCP server — so a DAG can drive an agent's tools with retries, timeouts, artifacts and an approval gate around each call.

• Image: mancube/dagron-step-mcp — a Rust binary on distroless/cc (no shell, no package manager), runs as nonroot (uid 65532).
• Arch: linux/amd64, linux/arm64
• Runtime: spawns an MCP server as a child process and speaks stdio JSON-RPC (protocol 2024-11-05) to it · no ports
• Website: dagron.dev · Source / full docs: github.com/lucheeseng827/dagron · Apache-2.0

⁠This is a step, not a service

The mirror image of mancube/dagron-mcp⁠. That one is a server: it lets an agent drive dagron. This one is a task: it lets a dagron DAG drive an agent's tools.

Once a tool call is a task it inherits everything a task already has — retries with backoff, a timeout, captured output, artifacts between steps, an approval gate in front of it, and a place in the run's history. An in-process tool call has none of that.

So you usually do not deploy this image. You copy the binary into whatever image your task already uses — typically one that also carries the MCP server you want to call:

FROM your-task-image:1.2.3
COPY --from=mancube/dagron-step-mcp:0.10 \
     /usr/local/bin/dagron-step-mcp /usr/local/bin/dagron-step-mcp

Running the image directly requires the server named by DAGRON_MCP_STEP_SERVER to exist in the image: the step spawns it as a child process, and this runtime carries only the step binary. So direct execution fails unless you have added the server — copy the binary into an image that has one instead.

⁠Configure it

Entirely by environment, like every other dagron step:

⁠Use it in a DAG

tasks:
  - name: search
    docker_image: your-task-image:1.2.3   # with the binary COPY'd in
    command: ["dagron-step-mcp"]
    max_attempts: 3                        # the engine retries a flaky tool call
    retry_delay_secs: 5
    timeout_secs: 120                      # …and kills a hung one
    env:
      - { name: DAGRON_MCP_STEP_SERVER, value: "mcp-server-brave-search" }
      - { name: DAGRON_MCP_STEP_TOOL,   value: "brave_web_search" }
      - { name: DAGRON_MCP_STEP_ARGS,   value: '{"query": "dagron scheduler"}' }
      - { name: BRAVE_API_KEY, value_from: { secret: BRAVE_API_KEY } }

Secrets resolve at dispatch and are masked in task output.

⁠Tags

Pin in production — pick the newest published tag rather than copying a version from this page, which ages.

⁠See also

• docs/MCP.md — both directions of the integration, and the tool catalogue
• mancube/dagron-mcp — the server, for driving dagron from an agent