Aegis Python SDK

Audience: developers integrating an application with an Aegis gateway. Scope: installation, gateway configuration, provider clients, and inclusion-proof verification. Boundary: the SDK talks to a gateway and verifies proofs. It establishes nothing about the gateway's trustworthiness — see § Proof verification, which is the section that matters most.

Install

From this source tree — the supported path while registry versions lag:

pip install -e ./sdk/python

Registry caution. PyPI carries aegis-latent-sdk at 4.0.0; this source tree is 4.1.2. Installing from PyPI gets you different code from what this document describes. See Release Status.

Requires Python 3.11 or newer.

Configure a gateway

from aegis_sdk import build_headers, normalize_gateway_url

base_url = normalize_gateway_url("http://127.0.0.1:8080")
headers = build_headers(api_key="your-proxy-key", session_id="session-1")

normalize_gateway_url rejects malformed and unsafe URL forms rather than passing them through. build_headers assembles the session and authorization headers the gateway expects.

Provider clients

Drop-in wrappers that route through the gateway:

from aegis_sdk import OpenAI

client = OpenAI(
    aegis_base_url="http://127.0.0.1:8080",
    aegis_api_key="your-proxy-key",
    session_id="session-1",
)

response = client.chat.completions.create(
    model="gpt-4o-mini",
    messages=[{"role": "user", "content": "Hello, Aegis."}],
)

AsyncOpenAI, Anthropic and AsyncAnthropic follow the same shape.

Compatibility is bounded by the SDK's tests. It covers the provider surfaces and dependency ranges those tests exercise, not every provider version or endpoint.

Proof verification

This is the part that is easy to get wrong, and getting it wrong makes the verification meaningless.

from aegis_sdk import verify_proof_headers, require_trusted_root

# The root MUST come from a channel independent of the gateway that
# served the response. A root read from the same response proves nothing.
trusted_root = require_trusted_root(load_root_from_your_own_anchor())

ok = verify_proof_headers(response.headers, trusted_root=trusted_root)

A proof verified against a root supplied by the gateway that produced it establishes internal consistency and nothing more. The system would be attesting to itself. require_trusted_root exists to make the input explicit; it cannot tell whether the root you passed is genuinely independent, because a root is a root.

Lower-level entry points, when you hold the proof rather than the headers:

Schema and semantics: MMR Proof v1.

Streaming

A stream reports evidence as pending-terminal until its terminal summary commits, and no inclusion proof exists before then.

Check for the terminal marker. A client that treats connection close as success will silently accept a stream whose terminal commit failed — the gateway withholds the marker precisely so you can tell, and it cannot make you look.

Errors

AegisProofError on a well-formed proof means the proof did not verify. Treat that as a security event, not a retryable failure.

Secure defaults

• Never hard-code an API key. Read it from your environment or secret manager.
• Never log a key, a raw proof payload, or governed content.
• Verify proofs against an independently obtained root, always.
• Pin the SDK to an exact commit or version.
• Use HTTPS for any gateway that is not on localhost.

Develop

cd sdk/python
pip install -e ".[dev]"
ruff check src tests
mypy --config-file pyproject.toml
pytest -q

Related: Integrations Guide · MMR Proof v1 · Audit Endpoints · Boundaries