Touchstone

cv.touchstonePublished by touchstone.cvOfficial publisherv1.1.0Updated Oct 24, 2026

Bitcoin-anchored, tamper-evident audit log for AI agents — record, disclose and verify actions.

VerifiedStreamable HTTPWeb executableDeveloper ToolsSecurity & Monitoring

Overview

AI-generated overview

Touchstone records an AI agent's actions into a tamper-evident, Bitcoin-anchored audit log, signing each entry locally with your Ed25519 key.

What you can do
Record events: canonicalize a payload locally, sign the commitment with your key and append it to your recorder, optionally committing each field separately for selective disclosure later. Create shareable disclosure links for chosen entries and reveal only selected fields, with Merkle proofs against the signed payload hash. Verify disclosure bundles and fetch your recorder's public info and checkpoint state.
When to use it
Use it when you want an auditable, externally anchored record of what an agent did, and want signing to happen on your own machine rather than trusting a remote service with your key. The selective-disclosure path suits sharing proof of some fields while withholding others.
Requirements
Node.js 18 or later for the npm package over stdio, or the remote endpoint. A Touchstone recorder id, a Colony subject, and a Touchstone API key are required; recording also needs an Ed25519 seed given inline or via a key file. A recorder and key can be self-provisioned through the developer site.
Before you install
The server holds your Ed25519 signing key, which signs entries; keep the seed and key file private. The API key is sent to the Touchstone service, and disclosure, verify and recorder-info calls proxy to it. Recording appends entries to your recorder, and disclosure links make chosen fields publicly shareable, so review what you reveal.

Installation

In SourceWeft

  1. Open Touchstone in the dashboard and add it to a workspace.
  2. Connect Authorization token credentials. They are stored privately and never shown on public pages.
  3. Enable the server for the chats that should use its tools.

Web executable via Streamable HTTP. Remote servers run from the web runtime once configured in a workspace.

Use with an agent

Paste this prompt into Claude Code, Codex, Cursor or another agent — or into SourceWeft chat. The agent reads this server's install guide, shows you its publisher, endpoint and sign-in, and adds it to your client once you agree. Keys never go into a command.

Read https://sourceweft.com/mcp/cv.touchstone%2Ftouchstone/install.md and connect the MCP server it describes to my client. Before changing any config, show me its publisher, endpoint and sign-in method and wait for my OK. Never put an API key in a command or in a file I would commit; ask me where it should come from.

Read the install guide the agent follows

Other MCP clients

Add this to your client's mcpServers config.

{
  "mcpServers": {
    "touchstone": {
      "type": "http",
      "url": "https://touchstone.cv/mcp",
      "headers": {
        "Authorization": "Bearer <YOUR_TOKEN>"
      }
    }
  }
}

README

touchstone-mcp

Local MCP server for Touchstone — record what your agent did into a tamper-evident, externally-anchored log.

This server runs on your machine and holds your Ed25519 signing key. It signs each event locally and appends it to your recorder, so an agent only has to call touchstone_record({ event_type, payload }). The key never leaves this process. Canonicalization (JCS / RFC 8785) is done locally too, so a malicious or compromised server can't trick you into signing a different commitment than you intended.

Zero dependencies — Node 18+ built-ins only. It's a single file: read it before you trust it.

The remote MCP at https://touchstone.cv/mcp can't sign for you (Touchstone never holds your key), so its touchstone_record expects a signature you computed yourself. Run this server when you want frictionless local signing.

Install

bash
# one-off, no install:npx -y @touchstone-cv/mcp
# or vendor the single file:curl -O https://touchstone.cv/touchstone-mcp.mjs
# or clone:git clone https://github.com/Touchstone-CV/touchstone-mcp && cd touchstone-mcp

Configure

Point your MCP client at it over stdio:

json
{  "mcpServers": {    "touchstone": {      "command": "npx",      "args": ["-y", "@touchstone-cv/mcp"],      "env": {        "TOUCHSTONE_RECORDER": "rec_...",        "TOUCHSTONE_SUBJECT": "<your-colony-sub>",        "TOUCHSTONE_API_KEY": "tsk_...",        "TOUCHSTONE_SIGNING_KEY": "<base64 Ed25519 32-byte seed>"      }    }  }}
Env varRequiredMeaning
TOUCHSTONE_RECORDERyesYour recorder public id (rec_…)
TOUCHSTONE_SUBJECTto recordYour Colony sub — the recorder's subject
TOUCHSTONE_API_KEYyesAPI key minted on the recorder (tsk_…)
TOUCHSTONE_SIGNING_KEYto recordbase64 Ed25519 32-byte seed — kept by you, never sent
TOUCHSTONE_KEY_FILEaltPath to JSON {"seed_b64":"…"} instead of the inline seed
TOUCHSTONE_BASE_URLnoDefaults to https://touchstone.cv

To get a recorder + key, see touchstone.cv/developers — agents can self-provision one with their own Colony token (OAuth Token Exchange, RFC 8693), no browser required.

Tools

ToolWhat it does
touchstone_recordJCS-canonicalizes payload, signs the commitment locally, appends the entry
touchstone_discloseCreate a shareable /d/<token> disclosure link (proxies to the service)
touchstone_verifyVerify a disclosure bundle (proxies to the service)
touchstone_recorder_infoFetch your recorder's public info / checkpoint state

Only touchstone_record uses your signing key; the rest proxy to the remote service over your API key.

Selective field disclosure

Call touchstone_record({ event_type, payload, selective_disclosure: true }) to commit each payload field separately — the client computes a salted-field Merkle root locally and signs that as payload_hash, storing the per-field salts. Later you can reveal only a subset:

js
touchstone_disclose({ seqs: [n], reveal: { n: ["field_a", "field_b"] } })

Revealed fields ship with Merkle proofs against payload_hash (which your signature already covers); withheld fields are salt-bound and their values never appear in the disclosure. The root computation matches the server and the verifiers byte-for-byte.

Verifying the log

A disclosure can be checked by anyone, with no trust in Touchstone — in the browser verifier, the standalone verify.php, or the gossip_check.py split-view checker. Those tools are served from the site (and are each a single auditable file); this repo is just the recording client.

License

Apache-2.0.

Source: README.md at commit 09777ca

Tools

0
This server asks for a credential such as an API key, so SourceWeft could not read its tools without one and has not indexed them.

Version history

1
  1. v1.1.0LatestSep 16, 2026

Score

85% of the applicable checks met

How complete this listing is, computed from the registry entry, the endpoint and public sources. Not a rating of the server and not a statement that it is safe or working today: reachability is a dated check, and no installs or reviews go into the score.

  • Reached in the last 30 daysRequired25 pts
  • Auth declaredRequired10 pts
  • Tools listed15 pts

    Answer tools/list without a credential, or ship a package that starts in a sandbox without one.

  • DescriptionRequired15 pts
  • Logo10 pts
  • Documentation15 pts
  • License10 pts

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