Cryptographic proof of existence — anchored to the Bitcoin blockchain.
Your AI agent stamps a file. Bitcoin records it forever. Even if OTSkit disappears tomorrow, the proof remains valid — verifiable by anyone using any OpenTimestamps-compatible tool.
OTSkit proves that a specific file existed before a specific Bitcoin block. That's it. That's the guarantee, and it's a strong one.
It does not prove:
- Who created the file
- That the file hasn't changed since
- Anything about legal validity in any jurisdiction
The proof is cryptographic, not legal. What it means in a legal context depends on your jurisdiction and circumstances. Consult a lawyer for use in legal proceedings.
The proof lives in a .ots file on your machine and in the Bitcoin blockchain. No subscription, no account, no server to trust. If OTSkit disappears tomorrow, every proof ever generated stays valid forever.
| OTSkit | OriginStamp | OpenTimestamps CLI | getAlby/ots-mcp | |
|---|---|---|---|---|
| Cost per stamp | Free | ~$12K/yr (500K stamps) | Free | Free |
| Proof format | .ots (open standard) | Proprietary (JSON/PDF) | .ots (open standard) | .ots (open standard) |
| Works if service disappears | ✅ Always | ✅ Always | ✅ Always | |
| TypeScript SDK | ✅ Native | ❌ | ||
| MCP integration (AI agents) | ✅ 8 tools | ❌ | ❌ | ✅ 6 tools |
| Local persistence (SQLite) | ✅ | ❌ Cloud only | ❌ Files only | ❌ |
| Auto-upgrade scheduler | ✅ | ❌ | ❌ | ❌ |
| Resilience (circuit breakers) | ✅ Per-calendar | ❌ | ❌ | |
| OAIS / PREMIS preservation | ✅ via Skills | ❌ | ❌ | ❌ |
| Open source | ✅ MIT | ✅ LGPL | ✅ MIT |
AI agent audit trail — Every document your agent processes gets a tamper-proof timestamp. Prove what your agent did, on what file, and when.
File integrity — Stamp contracts, reports, or source code. Verify later that nothing changed.
Software releases — Timestamp each build artifact or SBOM. Prove your release existed before a specific date.
Digital preservation — Generate OAIS/PREMIS-compliant preservation packages anchored to Bitcoin.
| Package | What it does |
|---|---|
@otskit/core |
OpenTimestamps protocol engine — zero dependencies, TypeScript-native |
@otskit/client |
Production SDK with circuit breakers, SSRF protection, auto-retry |
@otskit/mcp |
MCP server — 8 tools for Claude, Codex, and any MCP-compatible agent |
| OTSkit Skills | Agent skills for BagIt/OAIS/PREMIS digital preservation workflows |
New to MCP? → 5-minute setup guide for Claude Desktop
npm install -g @otskit/mcp
ots-mcp setup claude-code # or: claude, codexRestart your agent and ask: "Stamp this file and prove it exists on Bitcoin."
MIT License · Built on the OpenTimestamps open standard
