Running GPT-5.5 via Codex as Hermes's Main Model

Melvin Vivas · X post · 2026-07-04 · Open on X

Topics: AI Agents, Tool Use & MCP, LLM Fundamentals · Level: beginner

Summary

The creator runs Hermes Agent with GPT-5.5 through Codex as its main model. He asks experienced users whether they route different tasks to different models, raising the question of choosing models for each task in an agent.

Key points

• Hermes Agent can use GPT-5.5 through Codex as its main model.
• An open question: whether to use different models for different agent tasks (model routing).

Resources mentioned

• Hermes Agent · tool · github.com · free
  Nous Research's open-source AI agent with CLI, TUI and desktop interfaces. It now supports hands-free activation with a wake word.
  Also in: Inspecting Coding-Agent Traces Live with JSONL Viewer (Codex, Claude Code) (Melvin Vivas on X · notes), Hermes Agent: each bot is its own profile (Melvin Vivas on X · notes), An X research bot built with Hermes (Melvin Vivas on X · notes), Run Your Hermes Agent on Free LFM2.5-2.6B via OpenRouter (Melvin Vivas on X · notes) and 55 more
• 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
• GPT 5.5 · tool · openai.com · paid
  OpenAI models the creator used as the coding model inside Cursor.
  Also in: Models That Work With the Hermes Agent for Personal Productivity (Melvin Vivas on X · notes), Conductor Walkthrough: Running Parallel Coding Agents in Isolated Git Worktrees (Melvin Vivas on X · notes), Composer 2.5 as the Default Coding Model in Cursor (Melvin Vivas on X · notes), Which AI coding model to use for which task (Melvin Vivas on X · notes) and 2 more