Python SDK

The Python SDK (agent-receipts) provides tools for creating, signing, and verifying Agent Receipts in Python applications.

Repository: agent-receipts/sdk-py

Features

• Create and sign Agent Receipts with Ed25519
• Build and verify receipt chains
• Validate receipts against the JSON Schema
• Action taxonomy helpers and risk level utilities
• Full type annotations (PEP 484)

Quick example

Receipts are signed by a separate obsigna-daemon. Your code sends tool-call events over a Unix socket; the daemon holds the key, builds the receipt, signs it, and chains it. This is the canonical path — reach for it first.

from obsigna import DaemonEmitter

with DaemonEmitter() as e:  # uses AGENTRECEIPTS_SOCKET or the per-OS default
    e.emit(
        channel="my-app",
        tool_name="filesystem.file.read",
        decision="allowed",
    )

Start the daemon first — see Daemon Setup — then Quick Start walks the full emit → list → verify loop.

In-process signing (tutorial and testing only)

Not for production

This pattern keeps the signing key inside the agent process. Anyone with code execution in the agent can forge receipts. For real deployments, use the daemon-mediated path, where the daemon owns the key and your app only sends events over a socket.

from obsigna import (
    CreateReceiptInput,
    create_receipt,
    generate_key_pair,
    sign_receipt,
)

keys = generate_key_pair()

unsigned = create_receipt(
    CreateReceiptInput(
        issuer={"id": "did:agent:my-agent"},
        principal={"id": "did:user:alice"},
        action={
            "type": "filesystem.file.read",
            "risk_level": "low",
        },
        outcome={"status": "success"},
        chain={
            "sequence": 1,
            "previous_receipt_hash": None,
            "chain_id": "chain_session-1",
        },
    )
)

signed = sign_receipt(unsigned, keys.private_key, "did:agent:my-agent#key-1")

See Installation to get started.