DarkMatter MCP server

DarkMatter MCP Server

Universal MCP server that emits Context Passport records for AI agent decisions and actions. Drop into any MCP-compatible client (Claude Code, Cursor, Cline, Continue, ChatGPT Desktop, Zed, Goose, and others) to give your agent a commit / verify / replay / export toolset for verifiable, tamper-evident records.

Built by DarkMatter. Implements Context Passport v2.0, an open CC0 standard. Records emitted by this server use RFC 8785 (JCS) canonicalization and are byte-equivalent across the Python and TypeScript reference SDKs.

Install

In your MCP client's config (claudedesktopconfig.json, Cursor's mcp.json, etc.):

{
  "mcpServers": {
    "darkmatter": {
      "command": "npx",
      "args": ["-y", "@darkmatterhub/mcp-server"]
    }
  }
}

Restart the client. Five tools become available to your agent:

• darkmatter_commit — record an agent decision or action
• darkmatter_verify — check that the chain has not been tampered with
• darkmatter_replay — walk the full chain in order
• darkmatter_export — produce a portable proof bundle
• darkmatterlistsessions — see what sessions exist locally

Bundles explain themselves

darkmatter_export produces a bundle that a stranger can act on. Alongside the records it carries the format name, a link to the specification, whether the chain was intact at export time, and the exact command to verify it in Python or TypeScript, plus what a failure looks like.

That matters because the bundle is the artifact that leaves your machine. It goes to an auditor, a regulator or a counterparty who has never heard of this format, and the whole claim is that they can check it without trusting whoever sent it. A bundle that does not say how is asking to be trusted.

Local by default, published when you ask

With no configuration the server keeps every record on your own disk. The chain verifies offline through darkmatter_verify, so you can evaluate the whole idea without an account.

Set an API key to publish records and get a link somebody else can check:

commit reports which of the two happened, in the storage field. If publishing fails the record is still committed locally and the error is returned alongside it, so a network problem cannot cost you the record.

Changed in 0.3.0. Earlier versions returned a

https://darkmatterhub.ai/r/{id} link for every commit while making no

network calls at all, so the link always 404ed. A verification URL is now

returned only when there is a published record behind it.

What gets captured

Whatever the agent (or user) explicitly invokes via darkmatter_commit. Auto-capture of every tool call without explicit invocation is a separate component (see Auto-capture below).

Example agent flow:

User:    Approve the refund for order #1247 and record the decision.
Agent:   Calls refund_order(1247).
Agent:   Calls darkmatter_commit({
           input: "Approve refund for order #1247",
           output: "Approved. $84.00 refunded to original payment method.",
           role: "compliance",
           event_type: "commit"
         })
Result:  { ok: true, passport: {...}, storage: "local", verify_url: null,
           note: "Saved locally and verifiable offline..." }

Shortened. The full README is on GitHub.