Quickstart — 5 minutes, no cloud

pip install attestlayer

1. Wrap one function

import attest

@attest.action(system="gmail", verb="send", target="to")
def send_email(to, subject, body):
    return gmail.users().messages().send(userId="me", body=msg).execute()

send_email("arun@newco.com", "Follow-up", "…")

The first external send pauses: the console asks y / n / e. Approve it.

2. Look at the ledger

attest ledger
attest verify          # hash chain intact

#1  2026-09-15 10:02:11 gmail.send → arun@newco.com  ask  approved  acknowledged  5b1c…

acknowledged means the API returned an id and nothing was read back. Give Attest the client the agent already holds and it reads the message back and compares recipients, subject and the SENT label:

at = attest.Attest(readers={"gmail": gmail})     # or an OAuth token string

#2  … gmail.send → arun@newco.com  ask  approved  verified  …

3. Set one policy

attest.yaml:

policies:
  - match: { verb: [send, share], target: external }
    decision: ask
  - match: { verb: [delete, pay] }
    decision: ask
  - match: { system: hubspot, verb: update }
    decision: act

4. Don't label anything

@attest.action                                                   # send_email ⇒ unknown / send
def send_email(to, body): ...

@attest.action(method="POST", url="https://api.someweirdcrm.io/v2/leads")   # ⇒ someweirdcrm / create
def create_lead(name, email): ...

An app Attest has never seen is still recorded, decided, gated, and — with http_get= — read back by convention (GET /v2/leads/{id}) and verified. Run examples/unknown_app.py to see all three rungs.

5. Whole agent, one line

=== "LangGraph"

from attest.adapters import langgraph as attest_lg
tools = attest_lg.wrap_tools(tools, at, mapping={"send_email": {"system": "gmail", "verb": "send", "target": "to"}})

=== "OpenAI Agents"

from attest.adapters import openai_agents as attest_oa
tools = attest_oa.wrap_tools(tools, at, mapping=mapping)

=== "MCP (zero code)"

{ "mcpServers": { "gmail": { "command": "attest-mcp",
    "args": ["--upstream", "npx -y @modelcontextprotocol/server-gmail", "--server", "gmail"] } } }

Nothing about how you built the agent changed.