Debate Codex — Agentic Dev Days 2026

Debate Codex

Magnus Gille·gille.ai·magnus@gille.ai
Agentic Dev Days 2026 · 10 min

01 — The Premise

2026 Is The Year Of The Agents.

What shape an agent should take — that's still up for debate.

02 — The Design Space

The shape of an agent can be
almost anything.

Monolith

Role Cast

Swarm

Dumbbell

03 — Where This Started, Feb 2026

It started at a meetup.
A live multi-agent demo.

Demo

Claude Code, multi-agent

Architect. Tester. Reviewer. PM.

Q1

Why split roles at all?

Q2

And why these roles?

04 — A Conversation Over Coffee

"

Honestly?
I'm not sure. It's all very new.
Maybe the best thing is to just ask the agent to be adversarial — but truth-seeking.
Like a skilled, senior engineer
who's a little bit grumpy.

— paraphrased, from memory

05 — Add Diversity

One grumpy senior is good.
One with a fresh perspective is sharper.

Fresh
Context

+

Different
Model

+

Different
Harness

Claude Code spawns a headless Codex. /debate-codex

06 — How The Skill Works

The draft
goes through the wringer.

a plan a spec an architecture an implementation an ADR a thought

Draft

→

Critique

→

Respond

→

Archive

←←← multi-round ←←←

07 — A Conviction

Leave A Fossil Record.

Then Read The Fossils.

08 — The Fossil Record

The trace
speaks.

94 Debates

1,209 Critique Points

76% Only Caught By Codex

70% major or critical.

Round 1 → Round 2: the debate converges.

Round 1

842

Round 2

352

58% fewer points raised after dialogue.

09 — Greatest Hits

Selected verdicts.

"rsync --delete — catastrophic data loss risk."

mgc-to-mimir · saved my data

"A DSL pretending to be markdown — a time bomb."

hugin-v2-orchestrator

"Complexity theatre with internal contradiction."

skills-sync

"Retrospective validation is structurally broken. Will not happen."

debate-self-improvement · the debate debated itself

"A dishonest API through the back door."

tcc-permissions

10 — Meanwhile, March 2026

The ecosystem
caught up.

codex-plugin-cc

OpenAI · Mar 2026

Single-shot review

Code & PR diffs

Session-scoped output

/debate-codex

handmade · Feb 2026

Multi-round debate

Plans · specs · ADRs · thoughts

Persistent JSON archive

Same DNA. Different scope.

11 — Take It Home

The shape of an agent

Is Up For Debate.

So have one.

Adversarial. Truth-Seeking. Grumpy.

Different model. Different harness.
Leave a fossil record.