Build Failure Analyst

June 10, 2026 · View on GitHub

Delegate to the build-failure-analyst agent defined at .github/agents/build-failure-analyst.agent.md to analyze the binary log of the build that just ran and post a PR review when (and only when) the build failed.

Instructions

  1. Read the agent-context environment variables: GH_AW_BUILD_OUTCOME, GH_AW_BINLOG_PATH, GH_AW_BINLOG_HOST_PATH, GH_AW_PR_NUMBER, GH_AW_PR_HEAD_SHA, GH_AW_WORKSPACE.

  2. If GH_AW_BUILD_OUTCOME == 'success', the build did not actually fail — there is nothing to analyse. Call noop with the message "Build succeeded — no analysis required." and stop.

  3. Otherwise, launch the build-failure-analyst agent as a background task (task tool, agent_type: "general-purpose", model: "claude-opus-4.6", mode: "background"). In the sub-agent prompt include:

    • All six GH_AW_* environment values verbatim so the sub-agent knows which binlog to query (GH_AW_BINLOG_PATH is the in-container path /data/build.binlog exposed by the binlog-mcp MCP server) and where to post.
    • A reminder that the binlog is live-queryable through the binlog-mcp MCP server: the sub-agent should call MCP tools such as binlog_overview, binlog_errors, binlog_warnings (and others as needed) with binlog_file: "$GH_AW_BINLOG_PATH", rather than reading pre-dumped JSON files.
    • A reminder that the parent workflow noops immediately and that the sub-agent itself is responsible for calling add_comment (summary) and create_pull_request_review_comment (inline ```suggestion blocks).
    • A reminder that submit_pull_request_review is not a safe output for this workflow — inline comments stand alone.

  4. Immediately after launching the background task — do NOT wait for it to finish and do NOT read its result — call noop with a brief status message such as "Build-failure analyst launched in background for PR #N. It will post the analysis directly.". Then stop.

Important: Reading the background agent result would pull its entire conversation (including every binlog query and every source file it inspected) into your context. Do not call read_agent or any equivalent after calling noop.