cred-protocol

Async Python client and FastAPI dependency for the Cred Protocol trust evaluation API — composite trust scores (credit, sybil resistance, identity) for any Ethereum wallet, with policy templates and gates.

pip install cred-protocol            # core client (httpx)
pip install "cred-protocol[fastapi]" # + FastAPI dependency
pip install "cred-protocol[x402]"    # + Know Your Agent hooks for x402 sellers

Quick start

import asyncio
from cred_protocol import CredClient

async def main():
    async with CredClient(api_key="cred_sk_...") as cred:
        result = await cred.evaluate(
            wallet_address="0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045",
            policy="standard",
        )
        print(result.trust_score)  # 0-100
        print(result.trust_tier)   # TrustTier.VERIFIED
        print(result.all_passed)   # True

asyncio.run(main())

Custom gates instead of a policy template:

result = await cred.evaluate(
    wallet_address="0x...",
    gates=["human", "verified", "established"],
    operator="WEIGHTED",
    weights={"human": 0.4, "verified": 0.35, "established": 0.25},
    composite_threshold=60,
)

FastAPI

import os
from fastapi import Depends, FastAPI
from cred_protocol import TrustResult
from cred_protocol.fastapi import require_trust

app = FastAPI()

@app.get("/resource")
async def get_resource(
    trust: TrustResult = Depends(require_trust(api_key=os.environ["CRED_API_KEY"], policy="standard")),
):
    return {"wallet": trust.wallet_address, "score": trust.trust_score, "tier": trust.trust_tier.value}

require_trust(..., on_fail="deny" | "challenge" | "pass") returns 403, 402 or lets the request through when the wallet fails the policy.

Screen x402 payers (Know Your Agent)

Selling over x402? Screen every paying AI agent with Cred's Know Your Agent check before its payment settles:

import os
from x402.server import x402ResourceServer
from cred_protocol import register_cred_kya

server = x402ResourceServer(facilitator_client).register("eip155:8453", ExactEvmServerScheme())
register_cred_kya(server, api_key=os.environ["CRED_API_KEY"])

• Both servers. Works with x402ResourceServer (async) and x402ResourceServerSync, and with every x402 payment flow.
• Refusing a payer. A refused payer gets a 402 with error set to payer_sanctioned, payer_needs_review, payer_not_registered_agent or payer_screening_unavailable, and the payment never settles.
• Policy. CredKyaPolicy sets what to do with review verdicts, which flags always refuse, plain (non-agent) wallets, and what to do when Cred is unavailable.
• Failing open. Even when failing open, a sanctioned payer is always refused.

See the Python SDK docs.

Links

• Docs: https://docs.credprotocol.com/sdks/python
• API keys: https://app.credprotocol.com/dashboard/keys
• Trust evaluation API base URL: https://validator.credprotocol.com (override with CredClient(base_url=...))

MIT License.