Sentinel SDK

Oversight infrastructure for AI agents.

Sentinel adds human-in-the-loop approval to any Python function your agent calls. Wrap the function with @oversight, and the SDK pauses execution, requests approval, and only runs once a human approves.

Install

pip install sentinel-oversight

Quick start

# 1. Create an account at https://app.pauseapi.app/signup
#    Copy the API key it returns.

# 2. Wrap your function:

from sentinel import configure, oversight

configure(api_key="sk_live_…")

@oversight(
    risk_level="high",
    approvers=["sms:+15551234567", "alice@acme.com"],
    timeout_seconds=300,
)
def transfer_funds(amount: int, recipient: str):
    return stripe.transfers.create(amount=amount, destination=recipient)

When your agent calls transfer_funds(1000, "acct_xyz"):

1. Sentinel pauses execution and creates an approval on the backend.
2. Notifications fire to every approver in the list (rules below).
3. A human clicks Approve from a signed text/email link or the dashboard.
4. The wrapped function runs, and its return value flows back to the caller.

If rejected → ApprovalRejected(reason) is raised. If no response within timeout_seconds → ApprovalTimeout is raised (unless fallback="execute").

Approver formats

Each entry in approvers=[...] is a string. The format determines the channel.

You can mix formats — every approver receives a notification, the first decision wins.

Notification routing

• Email — fires if RESEND_API_KEY is set AND any approver looks like an email address. Email contains signed approve/reject links (HMAC-SHA256, scoped to that action_id and timeout window).
• SMS — fires if Twilio credentials are set AND an approver uses sms:.

By default, emails send from onboarding@resend.dev. To get branded approvals@yourdomain.app email, verify your domain in Resend (Pro plan).

SMS approvers — TCPA consent

To use sms:+1... approvers you must first register an opt-in record for each phone number. Sentinel won't create an approval whose approvers include an SMS destination without an active consent record — the API returns 400 SMS approver requires active SMS consent contact.

from sentinel import SentinelClient
client = SentinelClient()

# One-time, per phone number, after you've collected a real opt-in:
client.register_sms_contact(
    phone_number="+15551234567",
    display_name="Maya (CTO)",
    consent_source="onboarding_checkbox",       # e.g. "signed_form", "captured_web_form"
    consent_note="Checked the SMS opt-in box during signup on 2026-05-25",
)

Other helpers:

client.list_sms_contacts()           # all active + revoked contacts for this tenant
client.revoke_sms_contact("con_…")   # marks consent revoked; future SMS won't send

The customer can also reply STOP to any Sentinel SMS — the Twilio inbound webhook (/webhooks/twilio/inbound) automatically revokes their consent record. HELP returns a description and contact info. These two keywords are TCPA-mandated.

Default approvers

If you don't want to pass approvers=[...] on every decorator, set a default on your tenant. The API falls back to the tenant's default_approvers when the caller's list is empty.

from sentinel import SentinelClient
client = SentinelClient()

client.set_default_approvers(["sms:+15551234567", "ops@yourcompany.com"])
# now any @oversight(...) call without approvers uses these

Read or override via the web UI at https://app.pauseapi.app/contacts.

Resolution order when an approval is created:

1. The caller's explicit approvers=[...] (if non-empty)
2. The tenant's saved default_approvers
3. The global DEFAULT_APPROVERS env var on the API
4. 400 error if all three are empty

Risk levels

risk_level is a string the dashboard uses for prioritization. Allowed values: low, medium, high, critical. Required.

Configuration

Set via configure(...) or environment variables:

Exceptions

• SentinelError — base class for all Sentinel errors.
• SentinelConfigError — SDK was used without an api_key.
• SentinelAPIError(status_code, message, url) — backend returned a non-2xx.
• ApprovalRejected(reason, action_id) — a human rejected the request.
• ApprovalTimeout(action_id, timeout_seconds) — no decision before deadline.

Async

The decorator transparently supports async def functions:

@oversight(risk_level="medium", approvers=["alice@acme.com"])
async def send_email(to, body):
    await mailgun.send(to=to, body=body)

Audit log

Every approval creates a hash-chained audit trail. Fetch it:

from sentinel import SentinelClient
client = SentinelClient()
events = client.list_audit_events(action_id="act_…")  # or omit for full log

Each event has prev_hash and event_hash (SHA-256). Chain integrity can be verified by recomputing sha256(prev_hash + json(payload)).

LangChain

from sentinel.adapters.langchain import SentinelCallbackHandler

agent.run("…", callbacks=[SentinelCallbackHandler(risk_level="high")])

Install with pip install sentinel-oversight[langchain].

Links

• Website: https://pauseapi.app
• Dashboard: https://app.pauseapi.app
• API repo: https://github.com/PetrefiedThunder/sentinel-api
• This SDK: https://github.com/PetrefiedThunder/sentinel-sdk

License

MIT