Monitor Codex and Claude Code Subagents with agent-monitor

Melvin Vivas · X post · 2026-09-24 · Open on X

Topics: AI Agents, Tool Use & MCP, LLMOps, Deployment & Monitoring, AI Dev Tools & Productivity · Level: intermediate

Summary

The creator shares his open-source tool agent-monitor. It visualizes subagents spawned by Codex and Claude Code, with a traces view, token breakdown and cost tracking. It came in reply to his observation that GPT-6 Sol Ultra spawns Ultra-level subagents that use up limits quickly.

Key points

• Coding agents like GPT-6 Sol Ultra can spawn many subagents at the same high reasoning level, which uses up usage limits fast.
• agent-monitor visualizes Codex and Claude Code subagents.
• It offers an advanced traces view, a token breakdown and cost tracking.
• Watching subagents helps you find where tokens and cost are going.

Resources mentioned

• donvito/agent-monitor · repo · github.com · free
  Open-source dashboard that visualizes Codex and Claude Code subagents, with a traces view, a token breakdown and estimated cost.
  Also in: Agent Monitor: see traces, tokens and costs of your coding agents (Melvin Vivas on X · notes), Agent Monitor: Visualize Codex and Claude Code Subagents, Traces and Costs (Melvin Vivas on X · notes), Agent Monitor: Visualize Coding-Agent Subagents, Traces and Costs (Melvin Vivas on X · notes), Agent Monitor: Per-Model Usage Stats for Codex and Claude Code Agents (Melvin Vivas on X · notes) and 2 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
• Claude Code · tool · code.claude.com · paid · recommended by both Bashiri Smith & Melvin Vivas
  Build agents and pipelines from the terminal; the guide's main agentic coding tool.
  Also in: Create Claude Code Plugins with /plugin-authoring (Melvin Vivas on X · notes), Claude Code mods: customize behavior and UI with plugins (Melvin Vivas on X · notes), AI Engineer Roadmap Overview: From ML Foundations to RAG, Agents & Ops (Bashiri Smith on Facebook · notes), SkillsBento: Free Plugin Marketplace for Codex and Claude Code (Melvin Vivas on X · notes) and 101 more

Try this

• Use agent-monitor to track subagent traces, tokens and cost in Codex or Claude Code.