transcript.md

Written by the agent at the end of the coding-loop skill. The job, the plan, the approval, every file written, every validation run, and the report.

The job

User: /plan make detector.py beat the target in score.py on inbox.jsonl without memorizing senders or subject lines

Plan mode

Agent: I read detector.py, score.py and inbox.jsonl. Before I plan: may I use the sender’s domain and the domains of links in the body as evidence, and treat any domain outside the university’s and GitHub’s as suspect?

User: yes

Agent: PLAN.md written:

1. In detector.py, add a set of trusted domains: uw.edu, cs.washington.edu, github.com, canvas.uw.edu, library.uw.edu.
2. In is_phish, read the sender’s domain from the from field. An untrusted domain is a phish.
3. Find every http link in the body. A link to an untrusted domain is a phish.
4. Keep no keyword rule, so honest mail that says urgent or password is not flagged by the word alone.
5. Run python3 score.py and read the score against the target.

Tool calls refused in plan mode: write_file detector.py (before approve).

User: approve

The change

write_file detector.py:

#!/usr/bin/env python3
"""The phishing detector. is_phish(email) says whether one email is a phish."""
import json, re, sys

TRUSTED = {"uw.edu", "cs.washington.edu", "github.com", "canvas.uw.edu", "library.uw.edu"}


def domain_of(address):
    m = re.search(r"@([\w.-]+)", address)
    return m.group(1).lower() if m else ""


def is_phish(email):
    """True when the sender or any link in the body is outside the trusted domains."""
    if domain_of(email["from"]) not in TRUSTED:
        return True
    for link in re.findall(r"https?://([\w.-]+)", email["body"]):
        if link.lower() not in TRUSTED:
            return True
    return False


if __name__ == "__main__":
    path = sys.argv[1] if len(sys.argv) > 1 else "inbox.jsonl"
    for line in open(path, encoding="utf-8"):
        e = json.loads(line)
        print("PHISH " if is_phish(e) else "ok    ", e["subject"])

Agent: detector.py: replaced the keyword rule with a trusted-domain check on the sender and on every link in the body.

The validation

execute_file score.py:

score 60 of 60  target 54 of 60  PASS

Before the change the baseline scored: score 32 of 60 target 54 of 60 below target

Report

The detector passes the target on the public inbox: 60 of 60 against 54. One file written, detector.py. If the hidden set has phish from trusted-looking senders, the next step is to check for credential requests in the body as well.