Magi

Claude Code, Codex CLI and Oh My Pi, working as peers. Evidence over agreement.

Three agents, one verdict, and a rule about what counts as proof.

What it does

You already run more than one coding agent. Magi lets them check each other's work.

Not "one model asks another for the answer." Two engineers who review each other, argue when they disagree, and settle it with something you can verify. A second model agreeing with the first proves nothing, so Magi is built around one rule:

EVIDENCE  >  REASONING  >  MODEL AGREEMENT

You do not call a tool. You ask in plain words, and the agent decides when a second opinion is worth it:

Ask Codex to independently review this implementation.

Have Claude fact-check these claims before answering.

Use Codex as an adversarial reviewer of this architecture.

Delegate the test implementation to Codex, then review its changes.

Each harness loads one Magi MCP server. A request goes to a session that is already running in the right directory, so the peer keeps its own context. If nobody is home, Magi starts a restricted headless process instead. Every exchange is written to a ledger under ~/.magi.

Related MCP server: ape

A consultation, start to finish

Here is one illustrative run, as it looks from your chair.

1. You tell Claude: "Have Codex review this before I merge it."

2. Claude sends Codex a REVIEW pinned to HEAD~1..HEAD, asks for file:line evidence, and keeps its own opinion out of the message.

3. Codex reads the diff in its own session and replies with four findings.

4. Claude opens the files and checks each one. Three hold. One is wrong, because the guard it says is missing sits two lines above the cited line.

5. Claude records the outcome (3 accepted, 1 rejected, 0 open) and tells you what it changed and why it dismissed the fourth.

Skip step 4 and Magi nags you: unreconciled cards are named on later calls, and more than three in one coordinator session hold new cards. magi log shows over time how often each peer's findings actually held up.

The rules

Modes

Headless requests return after launch in every mode. Pass wait: true to block for the reply inline. DEBATE, PARALLEL and BAKEOFF exist in the engine but are not in the MCP tool schema.

Options on a request

Three harnesses, every direction

Any of the three can consult the other two, and omp can consult a distinct omp session. Anything else that loads MCP servers can join: serve it under its own name (magi serve ... --as <name>) and a small shim inside its session lets it be answered. Oh My Pi ships with both halves.

Watch it work

The /magi deck, drawn with sample data.

magi install adds a Claude Code mod, magi-view. Peer messages show as a plain header (Reply from omp · magi-… · round 2) over their body, without the protocol text, and your own Magi calls collapse to one line each with their delivery state. The model still reads every message as delivered.

The /magi deck shows what waits on you, the three units with the cards in flight between them, every agent working on a card, the last messages, a seven-day ledger and the provider switches. A band above the prompt appears only when a delivery fails, and the status line reads Magi: claude ✓ · codex – · omp ✓ · 1 working here. Details are in install.md.

No mod? The terminal covers the same ground:

Memory that all three share

remember, recall and forget keep notes in SQLite, one bank per repository (worktrees share it). Requests can carry relevant recalled evidence, and anything already delivered is not repeated. magi memory export writes the bank as markdown.

Get started

You need Node.js 22.13 or newer (for built-in node:sqlite), git, and Claude Code and Codex CLI installed and signed in. Oh My Pi is optional and is wired in when Magi finds it.

git clone https://github.com/howeasy/Magi.git
cd Magi
npm install
node bin/magi.mjs install        # add --omp to set up Oh My Pi explicitly

1. Set "crossSessionInbound": "accept" in Claude's settings.json. The installer does not write it.

2. Restart every Claude Code, Codex and omp session. Each harness reads its MCP servers at startup.

3. Run node bin/magi.mjs doctor until it shows no FAIL row.

4. Open a session in a project that has a live peer and ask for a review.

The steps, with what each one checks, are in install.md, including the omp setup. More prompts and what each one triggers are in usage.md. To remove everything, see uninstall.md.

Documentation

Development

npm test              # offline: fake CLIs, an isolated state home per test, no model calls
PEER_E2E=1 npm test   # adds real Claude and Codex calls

Conventions, what is live and when, and where each kind of change belongs are in AGENTS.md. Private formats (the Claude inbox frame, the Codex desktop steer channel, the omp extension API) are pinned to the versions they were checked against, and transport-recon.md is the repair guide when one breaks.

Licence and credits

Magi is MIT licensed. The Claude Code mod's clock, pulse and layout follow Flightdeck (MIT); see NOTICE. Prior art lists the other projects whose ideas Magi took. The MAGI look is a nod to the display in Neon Genesis Evangelion.

Claude, Codex and Oh My Pi are products of their respective owners. Evangelion and MAGI are trademarks of their owners. This is an unaffiliated tool.