{"slug": "show-hn-runbook-v1-governed-workflow-execution-for-mcp-fail-closed", "title": "Show HN: Runbook.v1 – governed workflow execution for MCP (fail-closed)", "summary": "Runbook.v1, a new application-layer contract for Model Context Protocol (MCP) hosts, enables governed, versioned, and auditable workflow execution with fail-closed semantics, ensuring that enterprise workflows are executed as required rather than suggested. The reference implementation passes its 24-test conformance suite, covering schema validation, content hashing, tamper detection, and checkpoint observation. The project is released under the MIT license.", "body_md": "**Deterministic at the host boundary. Free reasoning between checkpoints.**\n\nrunbook.v1 is an application-layer contract for MCP hosts that need governed, versioned, auditable workflows. It answers a limitation in the current MCP interaction model: an MCP server can expose a tool or workflow, but the model still decides whether to invoke it and how completely to follow it.\n\nFor enterprise workflows, execution must be required, not suggested.\n\nA runbook is a versioned manifest resolved from a trusted skills server and executed by the host with fail-closed semantics:\n\n```\n{\n  \"runbook_id\": \"executive-snapshot\",\n  \"version\": \"4.2.0\",\n  \"mode\": \"required\",\n  \"failure_policy\": \"fail_closed\",\n  \"checkpoints\": [\n    {\"id\": \"cp-revenue-qb\", \"kind\": \"tool_call\", \"required\": true,\n     \"match\": {\"tool\": \"quickbooks_profit_and_loss\"}},\n    {\"id\": \"cp-emit\", \"kind\": \"condition\", \"required\": true,\n     \"condition\": \"final_output\"}\n  ],\n  \"completion\": {\"condition\": \"final_output\", \"receipt\": true}\n}\n```\n\n**Acquisition is deterministic.** The host resolves the runbook by ID + version from a trusted skills server. No semantic search. Content hash, schema, and prerequisites are validated before the first model call.**Version pinning is absolute.** The exact version is bound for the life of the run. It is never pasted into chat as untrusted prose.**The tool surface is an allow-list.** The model can only see and call tools declared in the manifest.**Checkpoints are observed, not self-reported.** The host derives checkpoint state from the tool-call stream. The model never claims compliance.**Completion is host-evaluated.** The host decides whether the runbook completed and emits a machine-readable receipt.**Required mode is never silently downgraded.** If the host cannot honor the contract, it returns`runbook_failed`\n\ninstead of a normal answer.\n\n```\nschema/runbook.v1.schema.json   JSON Schema for the manifest\nspec/runbook-v1.md              The specification\nreference/python/               Reference host implementation\nconformance/                    Conformance test suite (24 tests)\nexamples/                       Example manifests\n```\n\nThe reference implementation passes its own conformance suite:\n\n```\npython3 conformance/run_conformance.py\nPASS: 24  FAIL: 0\n```\n\nThe suite covers: schema validation, content hashing, tamper detection, prerequisite fail-closed, checkpoint observation, checkpoint timeout, allow-list enforcement, receipt emission, and missing-runbook behavior.\n\nMCP won because it made agents practical. This makes them trustworthy. In enterprise procurement, those are the same word.\n\nMIT", "url": "https://wpnews.pro/news/show-hn-runbook-v1-governed-workflow-execution-for-mcp-fail-closed", "canonical_source": "https://github.com/CorpusIQ/runbook-spec", "published_at": "2026-08-18 20:34:11+00:00", "updated_at": "2026-08-18 21:11:53.531362+00:00", "lang": "en", "topics": ["ai-agents", "developer-tools", "ai-infrastructure"], "entities": ["Runbook.v1", "MCP"], "alternates": {"html": "https://wpnews.pro/news/show-hn-runbook-v1-governed-workflow-execution-for-mcp-fail-closed", "markdown": "https://wpnews.pro/news/show-hn-runbook-v1-governed-workflow-execution-for-mcp-fail-closed.md", "text": "https://wpnews.pro/news/show-hn-runbook-v1-governed-workflow-execution-for-mcp-fail-closed.txt", "jsonld": "https://wpnews.pro/news/show-hn-runbook-v1-governed-workflow-execution-for-mcp-fail-closed.jsonld"}}