stryda-sdk (Python)

One-file wrapper that puts a Stryda governance check in front of any tool call your agent makes, records the outcome afterwards, and hands you back a verifiable attestation.

This is Stryda's Layer 3 enforcement path — for agents that cannot route through MCP (custom scripts, third-party frameworks you do not control, internal services). For MCP-native agents, use /api/mcp directly — the pipeline at backend/mcp/pipeline.py already governs every call.

See docs/system-architecture.md for the full picture.

Install

Not published to PyPI. Install from the repo:

pip install -e ./packages/stryda-sdk-python
# Optional — offline attestation verification
pip install -e "./packages/stryda-sdk-python[verify]"

Quick start

import os
import stripe
from stryda_sdk import StrydaClient, governed, PolicyDenied, PendingApproval

stryda = StrydaClient(
    api_key=os.environ["STRYDA_API_KEY"],
    base_url=os.environ.get("STRYDA_BASE_URL", "https://api.stryda.ai"),
)

stripe.api_key = os.environ["STRIPE_KEY"]


def refund(charge_id: str, cents: int):
    try:
        return governed(
            stryda,
            tool="stripe.create_refund",
            action_type="payment_refund",
            args={"charge_id": charge_id, "amount_cents": cents},
            cost_estimate=cents / 100,
            agent_id="billing-agent",
            idempotency_key=f"refund:{charge_id}:{cents}",
            execute=lambda: stripe.Refund.create(charge=charge_id, amount=cents),
        )
    except PolicyDenied as e:
        print(f"Stryda denied refund: {e.reason}")
    except PendingApproval as e:
        print(f"Refund needs approval: {e.escalation_id}")

Manual two-step

check = stryda.check_action(
    tool="internal.delete_customer",
    action_type="hard_delete",
    args={"customer_id": customer_id},
)

if check.decision != "authorized":
    ...  # handle denied / escalated

import time
started = time.monotonic()
try:
    my_api.delete(customer_id)
    stryda.record_outcome(
        tool="internal.delete_customer",
        check_id=check.check_id,
        outcome="success",
        latency_ms=int((time.monotonic() - started) * 1000),
    )
except Exception as e:
    stryda.record_outcome(
        tool="internal.delete_customer",
        check_id=check.check_id,
        outcome="error",
        latency_ms=int((time.monotonic() - started) * 1000),
        error=str(e),
    )
    raise

Verifying attestations offline

Every record_outcome response includes an EdDSA JWT. The public key lives at https://api.stryda.ai/api/.well-known/jwks.json. The SDK's verifier:

from stryda_sdk import fetch_jwks, verify_attestation

jwks = fetch_jwks("https://api.stryda.ai")  # cache this
claims = verify_attestation(record.attestation, jwks, audience="mcp-governance")
# claims["audit_id"], claims["tool"], claims["decision"], claims["sub"] (user_id), …

No Stryda-specific format — any JWT library that understands EdDSA with Ed25519 will verify these tokens against the JWKS. PyJWT[crypto] works out of the box:

import jwt, httpx
jwks = httpx.get("https://api.stryda.ai/api/.well-known/jwks.json").json()
claims = jwt.decode(
    record.attestation,
    key=jwt.algorithms.OKPAlgorithm.from_jwk(
        next(k for k in jwks["keys"] if k["kid"] == record.attestation_kid)
    ),
    algorithms=["EdDSA"],
    audience="mcp-governance",
)

Error model

governed() raises the first two for you. If execute() raises, record_outcome is still called with outcome="error" before the exception propagates. If both the tool and record_outcome fail, the tool exception wins — a best-effort audit write should not shadow the real error.

What this SDK does not do

• It does not proxy your API calls. Your process still talks to OpenAI / Stripe / Twilio directly.
• It does not cache decisions. A denied policy at T0 might be authorized at T1 after policy edits.
• It does not retry. Use the same idempotency_key on retries — the control plane will return the stored decision instead of re-escalating.

Runtime requirements

• Python 3.10+.
• httpx>=0.26.
• cryptography>=42 only if you use verify_attestation (extra: stryda-sdk[verify]).