ContextAnalyzerTerminal

Know exactly which tool call ate your context window.

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Claude Code shows you total token usage -- but not which tool call caused the spike. Was it that Bash command that ran a find on your entire repo? The Read that loaded a 3,000-line file? CAT answers that question in real time.

It hooks silently into your Claude Code sessions, tracks token cost per tool call, builds rolling baselines, and fires an alert the moment something anomalous hits -- with a plain-language explanation of why.

Quick Start

git clone https://github.com/roeimichael/ContextAnalyzerTerminal.git
cd ContextAnalyzerTerminal
uv sync                         # install deps (Python 3.11+ and uv required)
uv sync --extra classifier      # optional: LLM root-cause analysis (~$0.0001/event)

context-analyzer-tool install   # inject hooks into Claude Code
context-analyzer-tool serve     # start the collector (keep this running)
context-analyzer-tool dashboard # open the live TUI

That's it. Use Claude Code normally -- CAT tracks everything in the background.

Why CAT?

Claude Code's built-in /cost and /context commands show snapshots -- no trends, no per-tool attribution, no cache TTL awareness. CAT fills that gap:

• You'll know which tool type consistently burns the most tokens in your workflow
• You'll get warned before your context fills, with actionable suggestions (/compact, /clear)
• You'll stop guessing and start optimizing

What You Get

| Feature | What it does | |:--------|:-------------| | Per-tool-call tracking | See exactly how many tokens each Read, Bash, Grep, etc. costs | | Rolling baselines | Learns normal cost per task type using Welford's algorithm | | Anomaly detection | Flags tool calls that exceed baseline by configurable Z-score | | Root-cause analysis | Haiku classifier explains why in plain language | | Context cost breakdown | See fresh-session vs current overhead ratio | | Live dashboard | Rich TUI with sessions, cost timeline, and anomaly feed | | Notifications | Statusline badges, system alerts, Slack/Discord webhooks | | Multi-session | Tracks concurrent Claude Code sessions independently |

CLI Reference

context-analyzer-tool install         Install hooks into Claude Code
context-analyzer-tool uninstall       Remove hooks from Claude Code
context-analyzer-tool serve           Start the collector server
context-analyzer-tool dashboard       Launch the live TUI dashboard
context-analyzer-tool status          View active sessions and recent tasks
context-analyzer-tool anomalies       List recent anomalies with root causes
context-analyzer-tool context-cost    Show context cost breakdown
context-analyzer-tool health          Collector health check
context-analyzer-tool rtk-status      Show RTK integration status and savings
context-analyzer-tool prune           Clean up old data
context-analyzer-tool clear           Clear all stored data and start fresh

Configuration

Config lives at ~/.context-analyzer-tool/config.toml (created automatically on first install). Every setting can be overridden with environment variables using the CAT_ prefix.

[collector]
host = "127.0.0.1"
port = 7821

[anomaly]
z_score_threshold = 2.0      # Std devs above mean to flag
min_sample_count = 5          # Data points before detection kicks in
cooldown_seconds = 60         # Debounce duplicate alerts

[classifier]
enabled = true                # Requires: uv sync --extra classifier
model = "claude-haiku-4-5-20251001"

[notifications]
statusline = true             # Badge in Claude Code statusline
system_notification = true    # OS notifications (macOS/Linux)
in_session_alert = true       # In-session alert messages
webhook_url = ""              # Slack/Discord webhook

Environment variable overrides:

CAT_COLLECTOR_PORT=8080
CAT_ANOMALY_Z_SCORE_THRESHOLD=3.0
CAT_CLASSIFIER_ENABLED=false

How It Works

Claude Code hooks don't include token counts. CAT correlates two data streams:

1. Hook events (PostToolUse, SubagentStop, Stop, etc.) carry tool metadata
2. Statusline snapshots provide real-time token counts

The delta engine matches them by session ID + timestamps to compute per-call costs. Anomalies are detected via Z-score over a rolling 20-sample window per task type, then classified by Haiku.

Hooks + Statusline → Collector → Delta Engine → Anomaly Detection → Classifier → Notifications
                                       │
                                   SQLite DB
                                       │
                                   Dashboard

Contributing

We welcome contributions! Check out our Good First Issues for beginner-friendly tasks with clear guidance.

uv sync --all-extras          # Install with dev + classifier deps
uv run pytest tests/ -v       # Run full test suite
uv run ruff check src tests   # Lint
uv run pyright                # Type check (strict mode)

See [CONTRIBUTING.md](CONTRIBUTING.md) for architecture overview, reading order, and contribution guidelines.

Tech Stack

FastAPI + Uvicorn (async collector) -- SQLite + aiosqlite (persistence) -- Pydantic (validation) -- Typer + Rich (CLI/TUI) -- Anthropic SDK (optional classifier)

License

[MIT](LICENSE)

Source & license

This open-source MCP server is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: roeimichael
• Source: roeimichael/ContextAnalyzerTerminal
• License: MIT

Install and usage instructions live in the source repository linked above.