signet-auth

Cryptographic action receipts for AI agents. Sign every tool call with Ed25519 — works with LangChain, LangGraph, LlamaIndex, Google ADK, Pydantic AI, Smolagents, Semantic Kernel, OpenAI Agents, AutoGen, CrewAI, and more.

Install

pip install signet-auth

Quick Start

from signet_auth import SigningAgent

agent = SigningAgent.create("my-bot", owner="alice")
receipt = agent.sign("web_search", params={"query": "signet"}, target="mcp://local")
print(receipt.id)

Decorator Entry Point

For plain Python tools, the easiest way to adopt Signet is the decorator layer:

from signet_auth import SigningAgent, signet_tool

agent = SigningAgent.create("tool-bot", owner="alice")

@signet_tool(
    agent=agent,
    target="mcp://github.prod",
    audit_encrypt_params=True,
)
def create_issue(title: str, repo: str) -> str:
    return f"{repo}:{title}"

@signet_tool also supports:

• async tool functions
• custom tool_name
• explicit transport
• on_sign_error="warn" | "raise"

MCP Server Verification

If you enforce Signet at the execution boundary, use verify_request() with a durable nonce backend:

from signet_auth import FileNonceChecker, VerifyOptions, verify_request

nonce_checker = FileNonceChecker(".signet/nonces.json")
opts = VerifyOptions(
    trusted_keys=["ed25519:..."],
    expected_target="mcp://github.prod",
    nonce_checker=nonce_checker,
)

result = verify_request(request_params, opts)
if not result.ok:
    raise ValueError(result.error or "verification failed")
if not result.trusted:
    raise ValueError("untrusted signer")

ServerVerifyResult tells you both whether a receipt was present (has_receipt) and whether the signer was anchored to trust (trusted). FileNonceChecker is the default single-host pilot shape; InMemoryNonceChecker is still useful for tests and demos.

Framework Integrations

Install with framework extras:

pip install signet-auth[langchain]     # LangChain / LangGraph
pip install signet-auth[llamaindex]    # LlamaIndex
pip install signet-auth[google-adk]    # Google ADK
pip install signet-auth[pydantic-ai]   # Pydantic AI
pip install signet-auth[semantic-kernel] # Semantic Kernel
pip install signet-auth[all]           # All frameworks

Links

• Full documentation & source
• npm (@signet-auth/core)
• Rust (signet-core)

If Signet is useful to you, star us on GitHub — it helps others discover the project.