@otskit/mcp

OpenTimestamps MCP server — stamp, upgrade, and verify Bitcoin timestamps via AI agents.

Exposes a set of tools to any MCP-compatible agent so it can timestamp documents, monitor confirmation status, and verify proofs against the Bitcoin blockchain — all from a conversation.

Note on confirmation times: After stamping, a proof is pending until Bitcoin confirms it. This typically takes 10–60 minutes but can take several hours during network congestion. Use ots-mcp watch or upgrade_timestamp to monitor. A pending status is not an error.

Install

npm install -g @otskit/mcp

Agent setup

ots-mcp setup claude        # Claude Desktop
ots-mcp setup claude-code   # Claude Code CLI
ots-mcp setup codex         # Codex CLI

Each command writes the MCP entry into the agent's config file, makes a .bak backup if the file already exists, and skips if ots-mcp is already configured. Restart the agent afterwards to apply the changes.

CLI commands

Command	Description
`ots-mcp serve`	Start the MCP server (stdio transport)
`ots-mcp stamp <sha256>`	Stamp a SHA-256 hash against Bitcoin calendars
`ots-mcp upgrade <id>`	Check if a pending stamp has been confirmed
`ots-mcp verify <id>`	Verify a stamp against Bitcoin
`ots-mcp list [status]`	List stamps (`pending` / `confirmed` / `failed`)
`ots-mcp watch [minutes]`	Poll pending stamps in real-time (default: 5 min)
`ots-mcp check-pending`	Run one upgrade pass over all pending stamps
`ots-mcp scheduler install\|remove\|status`	Manage OS-level scheduler for auto-upgrades
`ots-mcp backup [dest]`	Backup the SQLite database
`ots-mcp setup <claude\|claude-code\|codex>`	Configure MCP for an agent

MCP tools exposed to agents

Tool	Description
`create_timestamp`	Stamp a SHA-256 hash against 4 public OTS calendars
`upgrade_timestamp`	Check if a pending stamp has been confirmed in Bitcoin
`verify_timestamp`	Verify a stamp — proves hash existed before a given Bitcoin block
`inspect_timestamp`	Inspect a stored proof file without network calls
`list_pending`	List stamps with status, retry count, and filters
`watch`	Open a terminal window monitoring pending stamps in real-time

Data directory

All data is stored in ~/.ots-mcp/:

~/.ots-mcp/
  ots-mcp.db       # SQLite database (stamps, proof files)
  config.json      # Optional config overrides
  ots-mcp.log      # Log file

Configuration

Create ~/.ots-mcp/config.json to override defaults:

{
  "stamp_enabled": true,
  "scheduler_interval_minutes": 30,
  "retry_max_attempts": 20,
  "calendar_timeout_ms": 10000,
  "esplora_url": "https://blockstream.info/api",
  "calendars": [
    "https://alice.btc.calendar.opentimestamps.org",
    "https://bob.btc.calendar.opentimestamps.org",
    "https://finney.calendar.eternitywall.com",
    "https://btc.calendar.catallaxy.com"
  ]
}

Development

npm run build    # production build
npm run dev      # watch mode
npm test         # run tests

Dependencies

@otskit/core — OpenTimestamps core logic
@otskit/client — OTS calendar client
@modelcontextprotocol/sdk — MCP SDK
better-sqlite3 — local database