Agent Monitor: see traces, tokens and costs of your coding agents

Melvin Vivas · X post · 2026-09-18 · Open on X

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

Summary

The creator shares Agent Monitor, his open-source tool for seeing what coding agents do behind the scenes. It shows subagents, detailed traces, token breakdowns and cost usage. It supports Codex, Claude Code, Pi and Hermes.

Key points

• Agent Monitor shows what your coding agents are doing behind the scenes.
• It supports traces from Codex, Claude Code, Pi and Hermes.
• It visualizes Codex and Claude Code subagents.
• It includes an advanced traces view, a token breakdown and cost tracking.
• It's useful for debugging agent behavior and controlling spend.

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: Monitor Codex and Claude Code Subagents with agent-monitor (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
• Pi · tool · x.com · free
  A customizable coding agent that can be extended through its Extensions API and connected to several model providers.
  Also in: Sign in with ChatGPT: Setting Usage Limits for Each App (Melvin Vivas on X · notes), Pi reaches v1.0 (Melvin Vivas on X · notes), Claude Code mods: customize behavior and UI with plugins (Melvin Vivas on X · notes), Customizing Your Coding Setup with Pi Coding Agent Extensions (Melvin Vivas on X · notes) and 39 more
• Hermes · tool · hermes-agent.nousresearch.com · free
  The AI agent the creator uses to automate making explainer videos. It is probably Nous Research's Hermes Agent, but the post does not say so.
  Also in: OpenAI DevDay recap: Dots, GPT-6.1 Sol, Codex Cloud, Agents API (Melvin Vivas on X · notes), Coworker: free open-source desktop AI coworker app (Melvin Vivas on X · notes), Coworker: An Open-Source Desktop Agent App for Local and Cloud Models (Melvin Vivas on X · notes), jsonl-viewer: Inspect Coding Agent Traces (Codex, Claude Code, Pi, Hermes) (Melvin Vivas on X · notes) and 13 more

Try this

• Install Agent Monitor to inspect traces, token use and costs of your coding agents.