cullis-sdk 0.1.0

Python SDK for Cullis — federated agent-trust network. E2E-encrypted agent↔agent messaging, x509 mutual auth, DPoP-bound tokens.

cullis-sdk

Python SDK for the Cullis federated agent-trust network.

The Cullis SDK is the library you import from your Python agent code to talk to a Cullis broker. It handles enrollment, mutual TLS / DPoP-bound authentication, agent discovery, session management, and end-to-end encrypted messaging — so your agent code stays focused on what it does, not on the wire format.

The SDK is one of three Python distributions in the Cullis monorepo:

Distribution	Purpose
cullis-sdk	Library you import cullis_sdk from your agent code (this one).
cullis-connector	End-user MCP server bridging Claude Code / Cursor / etc.
mcp-proxy	Org-level gateway (deployed as a container, not pip-installed).

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Install

pip install cullis-sdk

Python 3.10+ required.

For SPIFFE workload-API integration (enroll an agent using its SPIRE-issued SVID), install the optional extra:

pip install 'cullis-sdk[spiffe]'

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Quick start

from cullis_sdk import CullisClient

with CullisClient("https://broker.example.com") as client:
    client.login(
        agent_id="myorg::reporter",
        org_id="myorg",
        cert_path="reporter.crt",
        key_path="reporter.key",
    )

    agents = client.discover(capabilities=["order.write"])
    target = agents[0]

    session = client.open_session(
        target.agent_id, target.org_id, ["order.write"],
    )
    client.send(
        session_id=session,
        from_agent="myorg::reporter",
        payload={"text": "Place order #42"},
        to_agent=target.agent_id,
    )

The SDK does the heavy lifting: x509 mutual TLS to the broker, DPoP-bound bearer tokens for replay protection, ECDH key agreement for end-to-end encryption to the recipient agent, and (on receive) hash-chain verification of the per-org audit log.

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Architecture

       ┌──────────┐  mTLS + DPoP   ┌──────────┐  mTLS + DPoP  ┌──────────┐
       │ Agent A  │───────────────▶│  Broker  │◀──────────────│ Agent B  │
       │ (cullis- │                │ (Cullis  │               │ (cullis- │
       │   sdk)   │                │  Site)   │               │   sdk)   │
       └──────────┘                └──────────┘               └──────────┘
            │                                                       ▲
            └─── E2E-encrypted payload (ECDH, broker can't read) ───┘

The broker authenticates both endpoints, routes messages, and appends a tamper-evident hash-chain entry per send. It never sees the cleartext payload.

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Documentation

• Repository: https://github.com/cullis-security/cullis
• Site: https://cullis.io
• Issues: https://github.com/cullis-security/cullis/issues
• Quickstart: https://cullis.io/docs/quickstart/getting-started/

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License

Functional Source License 1.1 with Apache-2.0 future grant (LICENSE). You can use, modify, and self-host the SDK for any non-competing purpose; competing-use restriction lifts after two years to Apache 2.0.