How do I install Witnessd?

Witnessd is a local plugin. Install it using npm package: witnessd-mcp and add the generated configuration snippet to your AI app's MCP config file. Then restart your AI app.

Is Witnessd safe to use?

Yes. Witnessd passed MCP Marketplace's automated security scan with a score of 10/10 (low risk). Every server on MCP Marketplace is security-scanned before it's listed; see the full security report on this page for the findings and permissions.

What credentials does Witnessd need?

Witnessd requires the following credentials or environment variables: WITNESSD_URL, EVM_PRIVATE_KEY, WITNESSD_API_KEY. You can find setup instructions on the server detail page.

What AI apps work with Witnessd?

Witnessd uses the Model Context Protocol (MCP) and works with any MCP-compatible AI app, including Claude, ChatGPT / Codex, Gemini, Copilot, Cursor, and more.

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Witnessd MCP Server

by witnessd

Developer ToolsLow Risk10.0Local

Free

Tamper-evident, on-chain-anchored evidence of what a URL or API returned. $0.02 per snapshot via x40

About

A neutral third-party witness for agents. witnessd independently fetches any public URL or API endpoint, hashes and timestamps the response, archives it, and returns a signed certificate. Hourly Merkle anchoring on Base means anyone can verify the record without trusting you, the counterparty, or us. Use it before paying an unfamiliar seller or acting on third-party data: $0.02 per snapshot via x402 (USDC on Base), certificate lookups free.

Security Report

10.0

Low Risk10.0Low Risk

Valid MCP server (2 strong, 4 medium validity signals). No known CVEs in dependencies. Package registry verified. Imported from the Official MCP Registry.

3 files analyzed · 1 issue found

Security scores are indicators to help you make informed decisions, not guarantees. Always review permissions before connecting any MCP server.

Permissions Required

This plugin requests these system permissions. Most are normal for its category.

HTTP Network Access

Connects to external APIs or services over the internet.

env_vars

Check that this permission is expected for this type of plugin.

What You'll Need

Set these up before or after installing:

Base URL of the witnessd service (default https://witnessd.vip)Optional

Environment variable: WITNESSD_URL

Wallet key used to auto-pay x402 invoices in USDC on Base (either this or WITNESSD_API_KEY)Required

Environment variable: EVM_PRIVATE_KEY

Prepaid witnessd credit key (alternative to EVM_PRIVATE_KEY)Required

Environment variable: WITNESSD_API_KEY

How to Install

Add this to your MCP configuration file:

{
  "mcpServers": {
    "vip-witnessd-witnessd": {
      "env": {
        "WITNESSD_URL": "your-witnessd-url-here",
        "EVM_PRIVATE_KEY": "your-evm-private-key-here",
        "WITNESSD_API_KEY": "your-witnessd-api-key-here"
      },
      "args": [
        "-y",
        "witnessd-mcp"
      ],
      "command": "npx"
    }
  }
}

Documentation

View on GitHub

From the project's GitHub README.

witnessd-mcp

MCP server for witnessd — a neutral third-party witness for the machine-readable web.

Give your agent the ability to create tamper-evident evidence: witnessd independently fetches any public URL or API endpoint, hashes and timestamps the response, archives it, and issues a signed certificate. Snapshot hashes are Merkle-batched hourly and anchored on Base, so certificates verify forever — by anyone, without trusting the operator.

Use it before transacting with a counterparty ("witness their published price/terms"), before acting on third-party data ("witness what the API returned"), or whenever a dispute might later hinge on what a URL said at a moment in time.

Quick install

You use	Run this
Claude Code (skill + MCP server in one step)	`/plugin install witnessd --marketplace jschunter/witnessd-mcp`
Any agent with Agent Skills (Cursor, Codex, Copilot, Gemini CLI and others)	`npx skills add jschunter/witnessd-mcp`
Any MCP client, MCP server only	`npx -y witnessd-mcp` (config below)

The skill (plugin/skills/witnessd/SKILL.md) teaches an agent when a neutral witness is worth two cents: before paying an unfamiliar seller, before acting on third-party data, or when asked to prove what a page said. It also sets spending rules: at most 5 paid calls per task without approval, a one-line report of each call, and no paid retries in a loop. The MCP server gives the agent the tools.

On older Claude Code versions, run /plugin marketplace add jschunter/witnessd-mcp and then /plugin install witnessd@witnessd.

Tools

Tool	Price	What it does
`witness_url`	$0.02	Independent fetch + hash + timestamp + archive of a URL right now; returns snapshot id + signed certificate
`get_certificate`	free	Certificate for any snapshot id: manifest, Ed25519 signature, Merkle proof, Base anchor transaction
`retrieve_snapshot`	$0.05	The archived response body + certificate — works for any snapshot id, any payer (this is how third parties obtain evidence)

Install

npx -y witnessd-mcp

Claude Desktop / Cursor config:

{
  "mcpServers": {
    "witnessd": {
      "command": "npx",
      "args": ["-y", "witnessd-mcp"],
      "env": {
        "EVM_PRIVATE_KEY": "0x…"
      }
    }
  }
}

Payment — two options

Set one of these environment variables:

EVM_PRIVATE_KEY — a wallet key holding USDC on Base. The server auto-pays each call via x402 (the buyer only signs; no ETH needed for gas). Use a small dedicated wallet, never your main one.
WITNESSD_API_KEY — a prepaid credit key (buy a $1 pack via POST https://witnessd.vip/api/credits, x402-payable).

Optional: WITNESSD_URL to point at a different witnessd instance (default https://witnessd.vip).

Verify without trusting us

Certificates are self-verifying: leaf_hash = sha256(canonical-json(manifest)), Ed25519-signed, Merkle-proven into an hourly batch root anchored on Base (calldata 0x + wtns1 + root). Standalone checker: witnessd.vip/verify.js.

Privacy & scope

Certificates (hashes, timestamps, proofs) are public; archived content is delivered only to paying requesters and never republished. witnessd only witnesses what any stranger can see — no logins, no private networks, bodies ≤10 MB. Machine-readable service docs: llms.txt · openapi.json · /.well-known/x402.

MIT license.