Signet
A cryptographic trust layer for AI agent actions that signs every tool call as a hash-chained, offline-verifiable receipt, so an agent's actions and the authorization behind them can be proven rather than only logged.
Signet gives every AI agent tool call a signed, Ed25519-verifiable receipt and chains receipts together with a SHA-256 hash, so that anyone holding the public key can verify what an agent did offline, without trusting the platform that hosted the agent or the party that stored the logs. Modifying a field such as the tool name, parameters, timestamp or signer breaks the signature, and deleting or reordering entries breaks the hash chain.
Since version 0.11, the authorization behind an action also carries its own proof: who the agent is, who delegated authority to it, and who authorized that specific action. A signet proxy can wrap any MCP server to sign every tool call with no code changes, and the project ships TypeScript packages for a core signing library, MCP client and server integration, a Node adapter and a Vercel AI SDK integration. It targets MCP builders who need tamper-evident logging and security or compliance teams that need an audit trail independent of any single vendor.