Setup for OpenAI Codex

Connect SpecThis MCP server to OpenAI Codex using HTTP transport

Prerequisites

  • OpenAI Codex CLI or IDE extension installed
  • A SpecThis account — you must be logged in via your browser for OAuth authentication

Step 1: Add SpecThis MCP Server

Add the following to your ~/.codex/config.toml file:

[mcp_servers.spec-this]
type = "http"
url = "https://app.specthis.ai/api/mcp"

Important: Use mcp_servers (with underscore, not hyphen).

Optional: Advanced Configuration

You can customize timeout settings if needed:

[mcp_servers.spec-this]
type = "http"
url = "https://app.specthis.ai/api/mcp"
startup_timeout = 10
tool_timeout = 60

startup_timeout — Time in seconds to wait for server startup (default: 10)
tool_timeout — Time in seconds to wait for tool responses (default: 60)

Configuration File Location

The Codex configuration file is located at:

  • macOS/Linux: ~/.codex/config.toml
  • Windows: %USERPROFILE%\.codex\config.toml

Configuration is shared between the CLI and the IDE extension.

Step 2: Verify Connection

After adding the configuration:

  1. Restart Codex or reload your IDE
  2. The MCP server will connect automatically — your browser will open for OAuth authentication on first connection
  3. Test the connection by asking Codex:

    "Can you list my SpecThis plans?"

Official Documentation

For more details on Codex MCP configuration, see the Codex MCP Documentation.