Overview

wattop is a terminal monitor for Apple Silicon Macs that watches your coding agents and your hardware in one pane: every running Claude Code and Codex session, its subagents and workflows, and the CPU, GPU, power, thermals and memory of the machine running them.

brew install --cask jasonm4130/wattop/wattop
wattop

What it shows

• Claude Code and Codex, live. Every running session with its status, output tokens/s, context fill, estimated cost and $/hr, bound to its process’s CPU, GPU and memory.
• Subagents and workflows as a tree. Claude Agent spawns (nested and background), workflow runs with phase and progress, and Codex child threads, each with its own rate and cost.
• Apple Silicon hardware beside it. CPU/GPU/ANE/DRAM power, E- and P-cluster load, GPU, temperatures, fans, thermal pressure, memory and swap, network and disk, with two-minute history graphs.
• No sudo, no runtime dependencies. Reads IOReport and SMC directly instead of wrapping powermetrics (which needs root); one binary, macOS system frameworks only.
• Scriptable. --json streams one snapshot per interval as NDJSON; --once prints one and exits.

How it compares

Tool	Hardware power & sensors	Claude Code / Codex sessions	Subagent tree	Live TUI	Needs sudo
wattop	yes	both, live	yes	yes	no
mactop	yes	no	no	yes	no
asitop	yes	no	no	yes	yes
ccusage	no	both, plus others (reports)	no	no	no
Claude Code Usage Monitor	no	Claude, live	no	yes	no

wattop vendors mactop’s IOReport/SMC collector. Comparison checked against each project’s README in September 2026. If you only want hardware, mactop is excellent; if you want historical usage reports across many agents, ccusage is. wattop is for watching live agents and the machine running them at once.

Requirements

Apple Silicon (arm64) with macOS 14 or newer. wattop links Apple’s private IOReport framework through CGO, so there is no Linux or Intel build. Hardware support varies by chip and macOS version; run wattop doctor to see what resolved on yours, and see limitations.

This is an early-stage project. Token rates are 60-second transcript averages, and dollar figures are API-price estimates, not subscription balances. See honest labelling.

Documentation

• Install: Homebrew, a release archive, go install, or build from source.
• Usage: every flag, every key, token rates, the subagent tree and the JSON stream.
• Config file: config.toml keys, defaults and precedence.
• Themes: the four themes, hex accents and NO_COLOR.
• Doctor: what wattop doctor reports and when to run it.
• Honest labelling: what each number is, and what it is not.
• Pricing table: where costs come from and how the table refreshes.
• Limitations: known gaps, each with its evidence.
• Privacy: what wattop reads, and its one network request.
• Troubleshooting / FAQ: $0.00/hr, missing sessions, 0 RPM fans and more.