Stop your agents
before they stop you.

import re
from apl import PolicyServer, Verdict

server = PolicyServer("guard")

@server.policy(name="redact-ssn", events=["output.pre_send"])
async def redact_ssn(event):
    text = event.payload.output_text or ""
    if re.search(r"\d{3}-\d{2}-\d{4}", text):
        return Verdict.modify(
            target="output", operation="replace",
            value=re.sub(r"\d{3}-\d{2}-\d{4}", "[SSN REDACTED]", text),
            reasoning="Redacted SSN",
        )
    return Verdict.allow()

if __name__ == "__main__":
    server.run()  # stdio by default

# Try it — no agent required
$ apl test ./guard.py -e output.pre_send \
    -p '{"output_text": "Your SSN is 123-45-6789"}'

MODIFY  ·  output → "Your SSN is [SSN REDACTED]"
        ·  Redacted SSN

import apl
apl.auto_instrument(policy_servers=["stdio://./guard.py"])

# Use your LLM SDK exactly as normal —
# output.pre_send now runs on every reply
from openai import OpenAI
resp = OpenAI().chat.completions.create(
    model="gpt-4o", messages=[...],
)
print(resp.choices[0].message.content)
# → already redacted if a policy fired

# Same idea, no Python required
name: corporate-compliance
version: 1.0.0

policies:
  - name: confirm-eu-export
    events: [tool.pre_invoke]
    rules:
      - when:
          payload.tool_name: { matches: ".*export.*" }
          metadata.user_region: { in: [EU, EEA, UK] }
        then:
          decision: escalate
          escalation:
            type: human_confirm
            prompt: "🇪🇺 GDPR: confirm data export?"