Know when an agent is about to run out of context.
agent-watchdog is a macOS command-line daemon that watches coding-agent sessions running in cmux terminals, alerts before a session runs out of context or its prompt cache expires, and can optionally ask the agent to stop or write a handoff before that happens.
Claude Code is the supported provider today; the provider interface is built to add others (Codex, etc.) later.
Download for macOS
v0.1.0 Apple silicon 430 KB built 18 Sep 2026
Or install from the terminal:
curl -fsSL https://agent-watchdog.pages.dev/downloads/agent-watchdog-darwin-arm64.tar.gz | tar -xz && ./agent-watchdog/install.sh
Needs cmux and Node 26 on your PATH. Checksum, requirements, and what install.sh does
cache expires in 3m 40s
How it works
- Polls the sessions in your cmux terminals
- The daemon reads cmux's session store to find running Claude Code sessions and the terminal surface each one lives in.
- Estimates context and cache expiry from each transcript
- From a session's own transcript it works out how much of the context window is in use and when the prompt cache will expire.
- Notifies you at the thresholds you set
- A warning at 35% by default, a critical alert at 75%, and a nudge when a session sits idle with its cache about to expire. Alerts go through cmux notifications, with a macOS notification fallback.
- Shows the same status in the sidebar and the menu bar
- It keeps a context-percentage pill in the cmux sidebar and writes a status file that the optional menu bar app renders.
- Can ask the agent to stop or write a handoff
- Only when you turn on message injection, it types a short
[agent-watchdog]-prefixed message into the agent's terminal. That is off by default and guarded by safety checks.