Multi GPT Codex

Multi GPT is a Codex Skill plus MCP server for local parallel reasoning. It starts an async background job that runs multiple read-only codex exec stages, compares independent approaches, refines them, judges sufficiency, and returns a concise final answer.

Inspired by GPT Pro, Gemini DeepThink, and Grok MultiAgents; implemented as a local Codex parallel-reasoning MCP + Skill.

Requirements

• Codex CLI available on PATH
• Node.js available on PATH
• A Codex environment that can register local MCP servers

What it does

• Starts long-running reasoning jobs through multi_gpt_start.
• Retrieves job state and final output through multi_gpt_status.
• Cancels mistakenly started running jobs through multi_gpt_cancel.
• Uses a Planner -> parallel Solvers -> parallel Refiners -> Loop(Merger -> Refiner -> Judge) -> Organizer pipeline.
• Keeps each Codex stage read-only with no approval prompts.
• Lets Codex CLI use its configured or recommended default model unless you pass a model argument.

Use it for complex design comparisons, deep code or architecture review, and long-form problem solving that benefits from several independent approaches. Do not use it for ordinary short answers.

Repository layout

skills/multi-gpt/
  SKILL.md
  agents/openai.yaml
mcp_servers/multi-gpt/
  server.mjs

Runtime job files are written under $CODEX_HOME/mcp_servers/multi-gpt/jobs/ and are intentionally ignored by git.

Install

The recommended path is to install the skill with Codex's skill-installer, then register the MCP server.

# In Codex, ask:
Install the multi-gpt skill from https://github.com/hehee9/multi-gpt/tree/main/skills/multi-gpt

Then clone the repository so the MCP server has a stable local path:

git clone https://github.com/hehee9/multi-gpt.git
cd multi-gpt

If you prefer manual installation, copy the skill into Codex:

mkdir -p "$CODEX_HOME/skills"
cp -R skills/multi-gpt "$CODEX_HOME/skills/multi-gpt"

If CODEX_HOME is not set, use ~/.codex:

mkdir -p ~/.codex/skills
cp -R skills/multi-gpt ~/.codex/skills/multi-gpt

Register the MCP server with Codex CLI.

On macOS/Linux:

codex mcp add multi_gpt -- node "$(pwd)/mcp_servers/multi-gpt/server.mjs"

On Windows PowerShell:

codex mcp add multi_gpt -- node "$PWD\mcp_servers\multi-gpt\server.mjs"

If you are updating an existing registration, remove it first with codex mcp remove multi_gpt, then run the codex mcp add command again.

Restart Codex after installing or updating the skill so it reloads skill metadata and MCP tools.

Usage

Ask Codex for Multi GPT or a parallel-reasoning review of a complex task. Codex should call:

1. multi_gpt_start with:
   • prompt (required)
   • files (optional absolute file paths)
   • model (optional; omitted means Codex CLI default or recommended model)
   • reasoning_effort (none, low, medium, high, or xhigh)
   • max_iterations (optional; default 5, clamped to 1..10)
2. multi_gpt_status with the returned job_id.
3. multi_gpt_cancel with the returned job_id if the job was started by mistake.

Runs usually take 5-20 minutes and commonly finish around 10-15 minutes, so poll only occasionally unless tighter monitoring is necessary.