Codex CLI MCP Setup

This guide shows you how to configure the Sita MCP server in Codex CLI to enable powerful codebase Q&A capabilities.

You must configure the MCP server for each repository you want to work with. Each repository requires its own configuration section with a unique repo ID.

Important: Codex CLI uses mcp_servers (with underscore) as the top-level key, not mcpServers like JSON-based tools.

Configuration Steps

Locate Configuration File

Open the Codex CLI configuration file located at:

~/.codex/config.toml

Create this file if it doesn’t exist.

Add MCP Server Configuration

Add an mcp_servers section to your TOML configuration file.

Configure Sita Server

Add the Sita MCP server configuration using TOML format (see examples below).

Save and Restart

Save the configuration file. The MCP server will be available next time you use Codex CLI.

Single Repository Configuration

To configure Sita for a single repository, add this to your ~/.codex/config.toml:

# IMPORTANT: Use mcp_servers (with underscore), not mcpServers
[mcp_servers.sita-qna]
command = "npx"
args = [
  "-y",
  "mcp-remote",
  "http://localhost:3000/api/mcp",
  "--header",
  "x-repo-id: YOUR_REPO_ID"
]
env = { "NODE_ENV" = "production" }

Replace YOUR_REPO_ID with your repository ID. The repo id can be copied from repos tab.

Multiple Repository Configuration

To configure multiple repositories, add separate server entries for each:

[mcp_servers.frontend-qna]
command = "npx"
args = [
  "-y",
  "mcp-remote",
  "http://localhost:3000/api/mcp",
  "--header",
  "x-repo-id: frontend-app"
]

[mcp_servers.backend-qna]
command = "npx"
args = [
  "-y",
  "mcp-remote",
  "http://localhost:3000/api/mcp",
  "--header",
  "x-repo-id: backend-api"
]

[mcp_servers.mobile-qna]
command = "npx"
args = [
  "-y",
  "mcp-remote",
  "http://localhost:3000/api/mcp",
  "--header",
  "x-repo-id: mobile-app"
]

Give each server configuration a descriptive name (like frontend-qna, backend-qna) to easily identify which repository it connects to.

Using Environment Variables

You can use an environment variable for the repo ID with the env field:

[mcp_servers.sita-qna]
command = "npx"
args = [
  "-y",
  "mcp-remote",
  "http://localhost:3000/api/mcp",
  "--header",
  "x-repo-id: ${REPO_ID}"
]
env = { "REPO_ID" = "your_repo_id" }

Create Configuration via Command Line

You can create the configuration file with this command:

mkdir -p ~/.codex && cat > ~/.codex/config.toml << 'EOF'
[mcp_servers.sita-qna]
command = "npx"
args = [
  "-y",
  "mcp-remote",
  "http://localhost:3000/api/mcp",
  "--header",
  "x-repo-id: YOUR_REPO_ID"
]
EOF

Then edit the file to add your actual repository ID:

nano ~/.codex/config.toml

Verification

After adding the configuration:

Save the ~/.codex/config.toml file
Run Codex CLI with a query about your codebase
The MCP server tools should be available for use

If you encounter a “string does not match pattern” error, it may indicate a compatibility issue between the MCP server’s tool naming convention and Codex CLI’s validation rules. Contact support if this occurs.

Next Steps

Set up MCP in Claude Code for CLI integration
Configure Cursor with MCP support
Try Cline for VSCode integration

Getting Started

Setup Guides

Codex CLI MCP Setup

Configuration Steps

Single Repository Configuration

Multiple Repository Configuration

Using Environment Variables

Create Configuration via Command Line

Verification

Next Steps

​Configuration Steps

​Single Repository Configuration

​Multiple Repository Configuration

​Using Environment Variables

​Create Configuration via Command Line

​Verification

​Next Steps

Configuration Steps

Single Repository Configuration

Multiple Repository Configuration

Using Environment Variables

Create Configuration via Command Line

Verification

Next Steps