Assay MCP Server

<strong>The open, recomputable evidence profile for privileged MCP tool actions.</strong>

Remote serverstreamable-httpPython

What is the Assay MCP server?

Assay MCP server is a hosted integration for AI assistants that speak the Model Context Protocol. The open, recomputable evidence profile for privileged MCP tool actions..

What the assistant can call

Once Assay is connected, these are the calls the assistant has available:

  • PositioningADR-033 · RFC-005
  • Output — What it is
  • Attestation — Export a bundle as an in-toto / DSSE statement (v0), anchor-pluggable
  • Deterministic — Same input, same decision — not probabilistic
  • Offline-first — No backend required for core enforcement and bundle verification
  • Quickstart — mkdir -p /tmp/assay-demo && echo "safe content" > /tmp/assay-demo/safe.txt assay mcp wrap --policy examples/mcp-quickstart/policy.yaml \ -- npx

Setting it up

Being a remote server, there is no local install. You register the endpoint with your client, authorise it once, and the tools appear.

Choosing this one

Among the developer tooling options, the useful question is rarely "what can it do" but "what does it cost you to run" — permissions, credentials, and how much of your context its toolset consumes. Assay's toolset — Positioning, Output, Attestation and 3 more — is a fair guide to whether it matches your workflow. It is maintained by rul1an; worth a glance at recent repository activity before you build anything load-bearing on it.

SyncDev reviews every entry in this directory against the project's own documentation before publishing, and revisits them as servers change.

Before you rely on it

  • Your data travels to the provider's service, so the usual questions apply about what you send and what they retain.
  • MCP clients confirm each tool call by default. Leave that on until you have watched what the assay mcp server does with a few real requests.

Available tools

ToolWhat it does
Positioning[ADR-033](docs/architecture/ADR-033-OTel-Trust-Compiler-Positioning.md) · [RFC-005](docs/architecture/RFC-005-trust-compiler-mvp-2026q2.md)
OutputWhat it is
AttestationExport a bundle as an in-toto / DSSE statement (v0), anchor-pluggable.
DeterministicSame input, same decision — not probabilistic.
Offline-firstNo backend required for core enforcement and bundle verification.
Quickstartmkdir -p /tmp/assay-demo && echo "safe content" > /tmp/assay-demo/safe.txt assay mcp wrap --policy examples/mcp-quickstart/policy.yaml \ -- npx @modelcontextprotocol/server-filesystem /tmp/assay-demo

How to install the Assay MCP server

{
  "mcpServers": {
    "assay": {
      "command": "npx",
      "args": ["-y", "@modelcontextprotocol/server-filesystem"]
    }
  }
}

Add to claude_desktop_config.json, then restart Claude Desktop.

Example prompts to try

  • Use Assay to Positioning.
  • Use Assay to Output.
  • Use Assay to Attestation.

Frequently asked questions

It connects Assay to MCP-compatible AI assistants such as Claude and Cursor, exposing 6 tools (Positioning, Output, Attestation, and more) that the assistant can call on your behalf. Instead of copying data back and forth by hand, the assistant works with Assay directly.