Bitcoin-anchored, tamper-evident audit log for AI agents — record, disclose and verify actions.
Most developer tooling work still happens through a UI a human drives. Touchstone MCP server moves it into the conversation instead. Bitcoin-anchored, tamper-evident audit log for AI agents — record, disclose and verify actions.
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.
The server publishes 4 tools. What each one is for:
touchstone_record — JCS-canonicalizes payload, signs the commitment locally, appends the entrytouchstone_disclose — Create a shareable /d/ disclosure link (proxies to the service)touchstone_verify — Verify a disclosure bundle (proxies to the service)touchstone_recorder_info — Fetch your recorder's public info / checkpoint stateConfiguration is passed through the environment: TOUCHSTONE_RECORDER, TOUCHSTONE_SUBJECT, TOUCHSTONE_API_KEY, TOUCHSTONE_SIGNING_KEY, TOUCHSTONE_BASE_URL. Treat anything key-shaped as a real credential — scope it to the minimum the server needs, and rotate it if it ever lands in a shared config.
The server ships on npm as @touchstone-cv/mcp, so your MCP client can launch it on demand — there is no separate build step. Add the server block to your client's configuration, restart it, and the tools register themselves.
This sits in the developer tooling group, where several servers overlap in what they claim to do but differ sharply once you actually set them up. Touchstone's toolset — touchstone_record, touchstone_disclose, touchstone_verify and 1 more — is a fair guide to whether it matches your workflow. It is maintained by cv.touchstone; worth a glance at recent repository activity before you build anything load-bearing on it.
We check each listing at SyncDev against the project's documentation before it goes live — if something here drifts out of date, it is a bug worth reporting.
| Tool | What it does |
|---|---|
| touchstone_record | JCS-canonicalizes payload, signs the commitment **locally**, appends the entry |
| touchstone_disclose | Create a shareable /d/<token> disclosure link (proxies to the service) |
| touchstone_verify | Verify a disclosure bundle (proxies to the service) |
| touchstone_recorder_info | Fetch your recorder's public info / checkpoint state |
{
"mcpServers": {
"touchstone": {
"command": "npx",
"args": ["-y", "@touchstone-cv/mcp"],
"env": {
"TOUCHSTONE_RECORDER": "your-value",
"TOUCHSTONE_SUBJECT": "your-value",
"TOUCHSTONE_API_KEY": "your-value",
"TOUCHSTONE_SIGNING_KEY": "your-value",
"TOUCHSTONE_BASE_URL": "your-value"
}
}
}
}Add to claude_desktop_config.json, then restart Claude Desktop.
| Variable | Description | Required |
|---|---|---|
| TOUCHSTONE_RECORDER | Configuration value read at startup. | Optional |
| TOUCHSTONE_SUBJECT | Configuration value read at startup. | Optional |
| TOUCHSTONE_API_KEY | Credential the server authenticates with. | Yes |
| TOUCHSTONE_SIGNING_KEY | Credential the server authenticates with. | Yes |
| TOUCHSTONE_BASE_URL | Endpoint or connection string the server talks to. | Yes |
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