Agent Debate

Agent Debate

Two agents hold a structured debate by appending to one shared markdown file. You write your turn, then poll until the other agent replies. When you genuinely need a human decision, you ask the user and both agents pause until they answer.

The engine that handles the file, locking, turn-taking, and polling is debate.sh next to this file. Always go through it — never hand-edit the debate file (concurrent edits corrupt it; the script locks).

SKILL_DIR="$(dirname "$(readlink -f ~/.claude/skills/agent-debate 2>/dev/null || echo ~/.agents/skills/agent-debate)")/agent-debate"
# Simpler: the script lives beside this SKILL.md. Resolve it once:
D="$HOME/.agents/skills/agent-debate/debate.sh"

Your identity

The user gives you your name, the peer's name, and a topic (default names: claude and codex). If the user only gives a topic, assume you are claude (Claude Code) or codex (Codex) per whichever tool you are, and the peer is the other.

Topic vs. brief — IMPORTANT

The topic is a short slug (a few words) — it becomes the shared filename, so keep it short and stable. Both agents MUST pass the same topic so they land on the same file (e.g. modal-vs-selfhost).

The actual subject — the paragraph of detail, requirements, constraints — is the brief, written into the file at init time, not the filename. The agent the user told to start passes it:

"$D" init "<short-topic>" <me> <peer> -   <<'EOF'
<the full paragraph(s): what we're deciding, context, constraints, success criteria>
EOF

If the user hands you a long paragraph, distill a short topic slug from it and put the paragraph in the brief. The joining agent just runs "$D" init "<short-topic>" <me> <peer> (no brief) and reads it via show.

Protocol (follow in order)

1. Open the channel. Create (or join) the file (idempotent; first caller is the initiator):

   • If you are the one the user told to start, init with the brief, then show to confirm, then post your opening position:

     "$D" init "<short-topic>" <me> <peer> -   <<'EOF'
     <the full brief: what we're deciding, context, constraints>
     EOF
     "$D" post "<short-topic>" <me> -   <<'EOF'
     <your opening argument>
     EOF
     

   • If you are joining, init without a brief, read the brief, then go to wait:

     "$D" init "<short-topic>" <me> <peer>
     "$D" show "<short-topic>"     # read the brief + any messages so far
     

2. Wait for your turn. Block until it's your turn / a human is needed / it's done:

   "$D" wait "<topic>" <me>
   

   • Claude Code: run this with run_in_background: true. The harness re-invokes you when it exits — don't block the foreground (sleep is blocked there anyway). It polls every 3 min internally.
   • Codex: run it as a normal blocking shell command. It sleeps internally and returns when there's something to do.
   • Exit code tells you what happened: 0 = your turn (peer replied), 20 = a question for the user is open, 30 = converged/done, 40 = peer posted a draft summary for you to review. wait also prints the full debate so you have fresh context.

3. Act on the result:

   • Your turn (0): Read the peer's latest argument. Think hard, look at the actual code/files if relevant, then respond — agree, refute, refine, or propose. Be a real debater: concede good points, push back on weak ones, converge toward the correct answer, not just a fast one.

     "$D" post "<topic>" <me> -   <<'EOF'
     <your response>
     EOF
     

     Then go back to step 2 (wait).
   • User needed (20): A question for the human is open. Surface it to the user verbatim (it's in the printed file under an ASK block) and stop to wait for their reply. When the user answers you, record it:

     "$D" answer "<topic>" -   <<'EOF'
     <what the user said>
     EOF
     

     Then go back to step 2 (wait). Both agents see the answer and resume.
   • Review summary (40): The peer posted a draft SUMMARY (the proposed conclusion). Review it critically against the whole debate: is anything missing, mis-stated, or unsupported? List concrete gaps.
     • Gaps found → post them (turn returns to the summarizer to revise).
     • It's complete and correct → accept it (this converges the debate):

       "$D" accept "<topic>" <me> -m "Reviewed — complete and accurate."
       

     Then continue: after gaps you go to wait; after accept you STOP.

   • Converged (30): An ACCEPT (or DECISION) is the last block. Summarize the outcome to the user and STOP. Do not start another wait, do not loop, do not keep polling. The debate is over until the user explicitly tells you to resume it (see "Stopping & resuming").
     • If the user wants the conclusion as a file: "$D" doc "<topic>" prints a clean standalone document (brief + accepted conclusion); redirect it where they want, e.g. "$D" doc "<topic>" > decision.md.

4. When YOU need the human (irreconcilable disagreement, missing requirement, a values/priorities call only the user can make) — instead of posting a message, ask the user:

   "$D" ask "<topic>" <me> -   <<'EOF'
   <a crisp question, with the options and the trade-off>
   EOF
   

   Surface the same question to your user, then go to step 2 (wait). Both agents pause on awaiting-user until someone records the answer.

5. Concluding. Two ways, depending on how formal the outcome needs to be:

   (a) Quick decision — for a simple agreed call. The agent whose turn it is:

   "$D" decide "<topic>" <me> -m "<the agreed decision + one line of rationale>"
   

   (b) Reviewed summary (recommended for anything you'll act on) — the conclusion gets peer-reviewed before it's final:

   • The agent whose turn it is when consensus is reached writes the draft summary (this is the "who summarizes" rule — the proposer summarizes):

     "$D" summarize "<topic>" <me> -   <<'EOF'
     <the full conclusion: what was decided, why, key trade-offs, follow-ups>
     EOF
     

   • Go to wait. The peer gets code 40, reviews, and either sends gaps back (you revise with another summarize) or accepts it.
   • On accept the debate converges. Both agents STOP. "$D" doc "<topic>" turns the accepted summary into a clean document on demand.

   After concluding (either way), summarize to the user and stop — do not wait again. The peer's wait returns 30 and it stops too.

Stopping & resuming

• Finishing means stopping. When the debate converges (a DECISION is the last block) both agents summarize and stop. Neither agent re-arms wait or keeps polling. Stay stopped until the user says otherwise — do not resume on your own.
• Resuming later. Only when the user explicitly asks to continue a previous debate, re-open the same file and pick up where it left off:

  "$D" latest                 # or use the topic the user names
  "$D" show "<topic>"         # re-read the full history incl. the decision
  "$D" post "<topic>" <me> -  <<'EOF'
  Reopening per the user: <what they want to revisit / new info>.
  EOF
  

  Posting after a DECISION reopens the thread (the decision is no longer the last block), and normal turn-taking resumes. The user must re-engage the peer too — don't assume the other agent is still listening after a finished debate.

Rules of engagement

• One turn at a time. Only post when wait says it's your turn. The engine enforces turn order (turn = the agent who didn't write the last message), so trust it rather than posting twice.
• Don't end the debate unilaterally. Use decide only when there's genuine agreement or the user has settled it. If you think you're done but the peer hasn't agreed, post "I propose we conclude with X — agree?" and wait.
• Ask the user sparingly but decisively. Debate the things you can reason about. Escalate (ask) only for genuine human calls. When you do, make the question and trade-offs concrete.
• Stay grounded. This is a real working session — read the files, run the checks, cite specifics. Don't debate in the abstract when you can verify.
• Keep going until resolved. Don't drop the thread after one exchange; loop wait → act → wait until decide (30) or the user stops you.

Inspecting state (optional)

"$D" status "<topic>"   # status= turn= last_msg_from= open_ask= file=
"$D" turn   "<topic>" <me>
"$D" show   "<topic>"   # print the whole debate
"$D" path   "<topic>"   # the resolved file path (under ~/.agent-debates/)
"$D" latest             # most recently created debate file (joiner shortcut)
"$D" list               # all debate files, newest first
"$D" doc    "<topic>"   # clean standalone document from the accepted conclusion

If the user starts the other agent and doesn't repeat the topic to you, you can find the active debate with "$D" latest and derive the topic from its filename (strip the dir and .md). Prefer an explicit topic when the user gives one.

File format (for reference — don't edit by hand)

# Debate: <topic>

<!--DEBATE
participants: architect,reviewer
initiator: architect
created: 2026-06-07T10:00:00Z
-->

<!--BRIEF-->
Decide whether datalabs runs lessons on Modal or self-hosted. Constraints:
budget < $X/mo, cold-start < 3s, must keep CSP/allow_root setup. Success =
cheaper at our scale without losing isolation.
<!--/BRIEF-->

<!--MSG from=architect ts=2026-06-07T10:00:00Z-->
I think we should use approach A because ...
<!--/MSG-->

<!--MSG from=reviewer ts=2026-06-07T10:03:00Z-->
Disagree — approach B handles edge case X ...
<!--/MSG-->

<!--ASK from=architect to=user id=q20260607100500 ts=2026-06-07T10:05:00Z-->
Do we prioritize latency or memory here?
<!--/ASK-->

<!--ANSWER to=q20260607100500 from=user ts=2026-06-07T10:09:00Z-->
Latency.
<!--/ANSWER-->

<!--SUMMARY from=architect ts=2026-06-07T10:12:00Z-->
Decision: approach A, latency-tuned. Rationale, trade-offs, follow-ups ...
<!--/SUMMARY-->

<!--ACCEPT from=reviewer ts=2026-06-07T10:15:00Z-->
Reviewed — complete and accurate.
<!--/ACCEPT-->

Block types: BRIEF (the subject), MSG (a turn), ASK/ANSWER (human interjection), SUMMARY (proposed conclusion, peer-reviewed), ACCEPT (sign-off, converges), DECISION (quick one-line conclusion, converges). The conversation (MSG) and the conclusion (SUMMARY/ACCEPT) live in the same file as distinct blocks; doc extracts just the conclusion.

Tuning

• AGENT_DEBATE_INTERVAL — poll seconds (default 180 = 3 min).
• AGENT_DEBATE_TIMEOUT — max seconds wait blocks before returning code 10 (default 0 = wait forever). Useful to cap Codex foreground waits.
• AGENT_DEBATE_DIR — where debate files live (default ~/.agent-debates).