Agent Monitor: Visualize Codex and Claude Code Subagents, Traces and Costs

Melvin Vivas · X video post · 2026-09-18 · 0:04 · 3,433 views · Open on X

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

Summary

Melvin Vivas shares Agent Monitor, an open-source GitHub project that shows what subagents are doing when you run OpenAI Codex or Claude Code. Besides showing the subagents, it has an advanced traces view, a breakdown of token use, and cost tracking. The post is a short demo video with no speech, and it points to the repo.

Key points

• Agent Monitor (github.com/donvito/agent-monitor) shows the subagents that OpenAI Codex and Claude Code start.
• It has an advanced traces view, so you can see what each subagent did, step by step.
• It breaks down token use, so you can see which agents or steps use the most tokens.
• It also tracks cost, which helps you keep coding-agent spending under control.
• This kind of observability for multi-agent coding tools makes subagent work easier to debug and tune.
• The post is only a 4-second demo video with no narration. Setup and usage details are in the repo README.

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: see traces, tokens and costs of your coding agents (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

• Look at the donvito/agent-monitor repo and follow its README to connect it to your Codex or Claude Code sessions.
• Use the traces, token and cost views to see where your subagent workflows use the most tokens and money.