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ChatGPT / Codex CLI Setup

Configure ACE MCP with OpenAI's ChatGPT and Codex CLI tools - Complete step-by-step guide.

Prerequisites
1

Node.js 18+ installed

Check with: node --version

2

OpenAI Codex CLI installed

3

OpenAI API key configured

Get API key from OpenAI →

4

ACE CLI installed and logged in

5

ACE server running

MCP Support in Codex CLI

OpenAI's Codex CLI supports MCP (Model Context Protocol) for connecting to external tools like ACE. This allows ChatGPT/GPT-4 models to access your project's memory infrastructure for persistent context.

1
Create MCP Config File

Create the MCP configuration file at the appropriate location for your operating system:

Config file location:

Create directory if needed: mkdir -p ~/.codex

2
Add ACE Configuration

Add the ACE MCP server to your config file:

Important: Customize Your Namespace

Replace my-project with a unique namespace for your project.

3
Run Codex CLI

Start the Codex CLI in your project directory:

4
Test ACE Integration

Try these prompts to test the ACE integration:

Store a memory:

"Store this memory: the project uses React 18 with TypeScript"

Query decisions:

"What decisions have been made about the database?"

Create an issue:

"Create an issue for the performance regression in the API"

Success!

If Codex responds by using ACE tools, your setup is complete!

Alternative: Direct REST API

If MCP is not available or you're using ChatGPT web interface, you can use ACE's REST API directly:

You can create custom GPT actions that call these API endpoints for ChatGPT Plus/Pro users.

Troubleshooting

"ace: command not found"

The ACE CLI is not in your PATH. Try these fixes:

  1. Reinstall ACE globally: npm install -g @ace3-memory/ace
  2. Check npm global bin: npm bin -g
  3. Add to PATH in your shell config file
ACE tools not appearing
  1. Verify ACE server is running: ace status
  2. Check config file for JSON syntax errors
  3. Restart Codex CLI after config changes
  4. Verify the config file path is correct
"Connection refused" errors
  1. Start ACE server: ace start
  2. Check health: curl http://localhost:7777/health
  3. Check if port 7777 is blocked by firewall

Available ACE Tools

Once configured, Codex CLI can use these 20+ ACE tools:

ace_rememberace_recallace_get_contextace_searchace_track_issueace_resolve_issueace_find_solutionsace_track_decisionace_best_practicesace_get_statsace_log_workace_architectureace_patternsace_manage_tagsace_graph_connectace_graph_traverseace_create_planace_generate_planace_observe

Next Steps