Paste Documentation URLs into Codex Instead of Using MCP

Melvin Vivas · X post · 2026-09-14 · Open on X

Topics: AI Dev Tools & Productivity, AI Agents, Tool Use & MCP, Prompt & Context Engineering · Level: beginner

Summary

The creator says that when Codex needs documentation, he just pastes the docs URL into the chat. He asks whether an MCP server is still needed for simply giving a coding agent access to documentation.

Key points

• To give Codex documentation context, paste the documentation URL straight into the prompt.
• For simple doc lookups, a coding agent that can fetch web pages may not need a dedicated MCP server.
• MCP may still be worth it for repeated, structured or authenticated access. Choose based on the use case.

Resources mentioned

• OpenAI Codex · tool · openai.com · paid
  OpenAI's coding agent. In the diagram it writes code, fixes review findings and drives the build loop. The creator also used it to make this video.
  Also in: An agent bot that installs and drives Codex on its own (Melvin Vivas on X · notes), Asking a Coder bot to install Codex (Melvin Vivas on X · notes), Sign in with ChatGPT: Setting Usage Limits for Each App (Melvin Vivas on X · notes), Codex Cloud Environments Must Be Saved & Published Before Use (Melvin Vivas on X · notes) and 240 more
• Model Context Protocol (MCP) · docs · modelcontextprotocol.io · free · recommended by both Bashiri Smith & Melvin Vivas
  An open standard for connecting LLM apps and agents to tools and data sources. The official docs explain how it works and how to build servers and clients.
  Also in: Grok Bot Templates: Sharing, Publishing and Safely Installing Bots (Melvin Vivas on X · notes), 8-Week Roadmap to a $200K+ AI Engineering Role (Bashiri Smith on Facebook · notes), OpenAI Agents API: Hosted Codex Harness for Long-Running Cloud Agents (Melvin Vivas on X · notes), Grok Bot Templates: How to Share, Publish, Install and Check Bot Blueprints (Melvin Vivas on X · notes) and 7 more

Try this

• Try pasting a library's documentation URL into your coding agent before setting up a docs MCP server.