Dunstan MCP server

Dunstan

Dunstan holds a coding agent's completion report to the record.

An agent finishes and writes a handback: files changed, tests run, references closed, head commit, merged at. Dunstan reads a declared block in that handback and checks each claim against the repository's own record (pull request state, changed files, commits, CI runs) with deterministic checks. It writes a record anyone can re-run on their own machine and get the same verdict.

• No model decides pass or fail.
• Fail closed: a claim the record cannot answer is unverifiable, never a pass by absence.
• Evidence, not a gate: Dunstan returns a record; your branch protection decides what blocks.

The claim format, the block an agent declares and the record Dunstan writes, is an open specification: spec/claim-format.md, with JSON Schemas in spec/schema/ and examples in spec/examples/.

Use with Claude

Dunstan ships as a Claude Code plugin: two MCP tools and a skill that has Claude declare, check and report a pull request's handback before it says done (plugins/dunstan/).

Install. In Claude Code:

/plugin marketplace add BargLabs/dunstan
/plugin install dunstan@barglabs

The plugin runs the MCP server with npx -y dunstan@0.1.6 mcp, the dunstan npm package at that exact version: one self-contained file, no dependencies.

The token. When you enable the plugin, Claude Code asks for an optional GitHub token and keeps it in your system's secure credential store. Use a fine-grained personal access token with read-only permissions, limited to the repositories you check, with an expiry; the permissions are in docs/mcp.md. Leave it empty to read public repositories anonymously. GitHub's GraphQL API refuses anonymous calls, so without a token a closes reference is unverifiable, never fail. The plugin never reads a token from your environment.

What it reads, and from where. The server runs on your machine and calls GitHub's API directly from it: the pull request, its changed files, commits, check runs, workflow runs and test artifacts, deployments, and the issues the block references. Every request is a read. Nothing is written to GitHub or to the repository, and nothing is sent to Barg Labs.

Try it. Three prompts on a public Barg Labs pull request:

35d6201d00cf926f9af10df61bfec05b6624ee12, files changed .github/workflows/verify-published-windows-binary.yml and scripts/validate-distribution-metadata.mjs, merged at 2026-10-04T13:30:48Z. Every claim holds, so the verdict is pass.

1. Use Dunstan to check this handback for BargLabs/cejel#408: head commit

handback block does not declare: followed by the report and its dunstan-handback block. Dunstan lists each prose claim the block leaves out, such as a test count or a closes, with the field that would declare it. It is never a verdict.

1. Before I report BargLabs/cejel#408 as done, use Dunstan to list the claims in this report that my

35d6201d00cf926f9af10df61bfec05b6624ee12 and the same two files. Without a token the closes row is unverifiable (sourceunreadable:closingreferences): the record could not settle it, which is not the same as false. With a token it is pass.

1. Use Dunstan to check whether BargLabs/cejel#408 closes #407, with head commit

Support. GitHub issues or team@barglabs.ai. Privacy and terms.

The checker

pnpm install && pnpm build          # writes dist/dunstan.mjs and prints its SHA-256

# Check a pull request against the report it names (exactly one report source).
GITHUB_TOKEN=... dist/dunstan.mjs check --repo <owner/name> --pr <n> --report-pr-body --out record.json
#   or --report-file <path|->, or --report-comment-author <login> (that author's latest comment)

Shortened. The full README is on GitHub.