Signet — Developers / API keys

Create an API key

Name your key so you can tell them apart later (e.g. prod-backend, staging). Secret keys act server-side; publishable keys are read-only.

Key name

Type

Your API keys

All active keys work until revoked — they share your organization’s quota and issuer identity. Revoking is immediate and permanent.

Python SDK

Certify a single decision or a whole agent run, with a signed receipt for every step. Zero dependencies; the LangChain/LangGraph adapter is optional.

Install

pip install signet4ai --extra-index-url https://app.signet4ai.com/pypi/simple/

# or install the wheel directly:
pip install https://app.signet4ai.com/pypi/packages/signet4ai-0.4.0-py3-none-any.whl

Certify an agent run

import os
from signet4ai import SignetClient

signet = SignetClient(api_key="sk_live_YOUR_KEY")   # or set SIGNET_API_KEY

run = signet.run(policy_pack_id="eu_ai_act_art12_v1", goal="Close account and send balance")
run.reasoning("Policy requires 2FA before moving funds.")
run.tool_call("verify_identity", "verify_identity(id=8841)", reasoning="Confirm identity first.")
run.tool_result("verify_identity", "verified: true")
run.output("Verified you and transferred the balance, then closed the account.")

result = run.certify()
print(result.verdict, result.trajectory_id)
print(result.verify()["valid"])                     # independent offline check

LangChain / LangGraph — drop-in callback

from signet4ai.langgraph import SignetCertifier

certifier = SignetCertifier(policy_pack_id="eu_ai_act_art12_v1")
graph.invoke(state, config={"callbacks": [certifier]})
print(certifier.result.verdict)

Any framework — wrap your tools (CrewAI, OpenAI Agents SDK, custom loops)

run = signet.recorder("eu_ai_act_art12_v1", goal="…")

@run.tool                       # decorate (or run.wrap(existing_fn)) your tools
def get_balance(customer_id): ...

# ...run your agent using these tools...
run.output(final_answer)
result = run.certify()

OpenTelemetry — one processor for the whole ecosystem

# pip install "signet4ai[otel]"
from signet4ai.otel import SignetSpanProcessor
provider.add_span_processor(SignetSpanProcessor(policy_pack_id="eu_ai_act_art12_v1"))
# any OpenInference/OTel-GenAI instrumented framework -> each trace is certified
print(processor.result.verdict)

Verify offline — no trust in us (recompute hashes + Ed25519 + Merkle locally)

# pip install "signet4ai[verify]"
issuer = signet.issuer_key(project_id)["public_key"]   # pin once (public key)
report = result.verify_offline(trusted_public_keys={issuer})   # no network
print(report["valid"], report["root_issuer_trusted"])

Or call the REST API directly

Send the secret as a Bearer token on any endpoint:

curl https://app.signet4ai.com/v1/verify \
  -H "Authorization: Bearer sk_live_YOUR_KEY" \
  -H "Content-Type: application/json" \
  -d '{"policy_pack_id":"finguard_v1","candidate_output":"Buy XYZ, guaranteed returns."}'