Context Monitor
A Claude Code plugin that tracks context window usage across sessions and displays a live HTML dashboard.
Zero token cost — runs as a Stop hook with no LLM calls.
What it does
Every time Claude finishes responding, the Stop hook:
- Reads token usage from the session transcript
- Detects the model and context window size (200K vs 1M)
- Updates a JSON file tracking the last 15 sessions
- Generates and auto-opens an HTML dashboard in your browser
The dashboard shows each session's project name, model, token usage, and a color-coded progress bar (green/yellow/red). It auto-refreshes every 5 seconds.
Install
As a plugin (recommended)
/plugin marketplace add ALLBLUEUK/context-monitor
Then open /plugin > Discover > install context-monitor.
Run /reload-plugins to activate.
Manual install
Copy hooks/stop.sh to ~/.claude/context-notify.sh, then add to ~/.claude/settings.json:
{
"hooks": {
"Stop": [
{
"hooks": [
{
"type": "command",
"command": "bash ~/.claude/context-notify.sh",
"timeout": 10
}
]
}
]
}
}
Requirements
jq (for parsing JSON transcripts)bash (Git Bash on Windows, native on macOS/Linux)
How it works
The dashboard is written to ~/.claude/context-dashboard.html. Session data is stored in ~/.claude/context-sessions.json. A lock file prevents duplicate browser windows from opening.
Context window detection
The hook defaults to 200K context. If token usage exceeds 190K, it auto-upgrades to 1M display.
Cross-platform support
- macOS: uses
open
- Linux: uses
xdg-open
- Windows (Git Bash): uses
start
License
MIT
ALLBLUEUK
