Codex: Codex MCP

{
  "mcp_servers": {
    "filesystem": {
      "command": "npx",
      "args": ["-y", "@modelcontextprotocol/server-filesystem", "/path/to/project"]
    },
    "github": {
      "command": "npx",
      "args": ["-y", "@modelcontextprotocol/server-github"],
      "env": {
        "GITHUB_TOKEN": "ghp_xxx"
      }
    }
  }
}

// .codex/mcp.json
{
  "mcp_servers": {
    "database": {
      "command": "npx",
      "args": ["-y", "@modelcontextprotocol/server-postgres"],
      "env": {
        "DATABASE_URL": "postgresql://localhost/mydb"
      }
    }
  }
}

// Alice's project MCP config
{
  "mcp_servers": {
    "postgres": {
      "command": "npx",
      "args": ["-y", "@modelcontextprotocol/server-postgres"],
      "env": {
        "DATABASE_URL": "postgresql://localhost/ecommerce"
      }
    }
  }
}

# Alice has Codex query the database
> Query the order count and total amount for the last 7 days

# Codex calls the database via MCP
→ Connected to postgres MCP server
→ Executing: SELECT COUNT(*), SUM(amount) FROM orders WHERE created_at > NOW() - INTERVAL '7 days'
→ Result: 1,234 orders, $89,567.89 total

> View the structure of the users table
> Query the number of active users
> Create a database migration for the new feature

> List pending Issues
> Create a PR and link it to Issue #15
> View review comments on PR #42

> Look up the API design doc in Notion
> Read the technical spec from Confluence
> Search the project Wiki for deployment guide

> View AWS S3 bucket list
> Check CloudWatch alerts
> List EC2 instance status

# Bob uses MCP for data-driven development
> 1. Query the structure of the products table in the database
> 2. Create TypeScript type definitions based on the Schema
> 3. Generate CRUD API endpoints
> 4. Write integration tests

# Codex via MCP:
→ Connected to postgres MCP server
→ Reading products table schema...
→ Creating TypeScript types...
→ Generating API endpoints...
→ Writing integration tests...
→ All done ✓

import { Server } from "@modelcontextprotocol/sdk/server";
import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio";

const server = new Server({
  name: "my-custom-server",
  version: "1.0.0",
});

server.tool("search_docs", { query: { type: "string" } }, async ({ query }) => {
  const results = await searchDocumentation(query);
  return { content: [{ type: "text", text: JSON.stringify(results) }] };
});

const transport = new StdioServerTransport();
await server.connect(transport);

{
  "mcp_servers": {
    "my-docs": {
      "command": "node",
      "args": ["/path/to/my-mcp-server.js"]
    }
  }
}