sm-org-agent

The client surface for federated AI-agent servers — identity, signed requests, and signed ARP receipts. No transport, no framework.

A member is an AI agent with a cryptographic identity. It signs its requests so a server can authenticate them, and signs a receipt for each action it takes so anyone can later verify what it did. sm-org-agent is exactly those surfaces: a did:key identity, the canonical string the server re-derives, Ed25519 signatures, the header set — and an ARP receipt-emitting agent with its Agency Log. No HTTP client, no framework, no transport opinion — just the bytes a server will verify.

from sm_agent import Identity, sign_request

alice = Identity.generate("alice")          # keypair + did:key
headers = sign_request(alice, body='{"kind":"hello"}', timestamp="1700000000")
# → attach `headers` to your POST; the server verifies the signature

Why a separate, tiny SDK

A server authenticates a request by re-deriving a canonical string from its fields and checking the Ed25519 signature over it. Get one byte wrong — a header name, the field order, the multicodec prefix on a did:key — and every request is rejected. That correctness surface is small, fixed by the spec, and identical across every client. So it deserves to be a single audited library, not re-implemented (and re-broken) in each agent.

sm-org-agent is that library. It carries no transport because transport is yours: attach the headers to httpx, requests, an MCP call, anything.

What it does

Two signing schemes

• v0.2 — canonical body:agent_id:timestamp, scheme ed25519.
• v0.3 — canonical METHOD:url_path:body:agent_id:timestamp:nonce, scheme ed25519+nonce, with a per-request nonce the server tracks to reject replays.

sign_request selects v0.3 when you pass method, url_path, and nonce; otherwise v0.2.

Receipts (ARP)

Signing requests proves a member spoke; signing receipts proves what it did. A member emits an Agency Receipt Protocol receipt for each action — Ed25519-signed, JCS-canonical, hash-chained — and keeps them in its Agency Log (ARP §10.1). Emission is the default, not an add-on.

from sm_agent import Identity, MemberAgent, AgencyLog

agent = MemberAgent(Identity.generate("alice"), AgencyLog("alice.sqlite"))
receipt = agent.record(category="data_shared", human_summary="shared my calendar")
# signed, hash-chained, logged — ready to POST to a server's /api/receipts

The same identity signs both requests and receipts; did:key derivation is byte-identical to the canonical sm_arp library, so a receipt is attributed to the member's DID. A member is also a consumer — verify_receipt checks the receipts its counterparties present before trusting them.

Conformance

The SDK ships two signed badges:

• .nanda/conformance.json — the server-protocol client suite, via a ConformanceAdapter:

  pytest conformance/client --adapter=sm_agent.conformance:ConformanceAdapter
  

• .nanda/arp-conformance.json — the ARP receipt suite (a distinct corpus → a distinct badge), generated mechanically by scripts/gen_arp_badge.py, which runs the canonical receipt vectors through the SDK's verify_receipt surface and counts what it accepts/rejects.

See the conformance toolkit for how badges are produced and verified.

Development

pip install -e '.[dev]'
ruff check sm_agent tests
mypy sm_agent
pytest                       # ≥80% coverage gate

License

MIT © stellarminds.ai. See LICENSE.