session-hygiene

A tiny Pi extension that adds a session-health light to the status bar.

🟢 ctx ok
🟡 ctx watch
🔴 ctx compact

Health is based on:

• Cumulative assistant cost for the current session branch
• Current context tokens from ctx.getContextUsage()

The extension also publishes a separate cache chip when token usage data is available:

• Prompt cache hit rate as cache <percent> from cacheRead / (input + cacheRead)

It only updates the status bar. It does not prompt, auto-compact, or inject guidance into responses.

Status Example

~/src/my-project (main)
↑34 ↓18k R868k W175k $1.982 7.4%/1.0M (auto)
🟡 ctx watch
cache 98%

Default Thresholds

| Level | Cost | Context | | --------- | ---- | ----------- | | 🟡 Yellow | $5 | 100K tokens | | 🔴 Red | $15 | 200K tokens |

Command

/session-hygiene

Opens interactive threshold configuration. You can pick a preset or enter custom values, then the status bar refreshes immediately.

Configuration

Config lives at ~/.pi/agent/extensions/session-hygiene/config.json:

{
  "yellow": { "cost": 5, "context": 100000 },
  "red": { "cost": 15, "context": 200000 }
}

If the file is missing or invalid, the extension falls back to the Default preset. Successful saves use 0600 permissions.

Presets

| Preset | Yellow | Red | | ---------------- | ----------------- | ----------------- | | Conservative | $2 / 60K tokens | $8 / 120K tokens | | Default | $5 / 100K tokens | $15 / 200K tokens | | Relaxed | $10 / 150K tokens | $25 / 250K tokens | | Custom | you decide | you decide |

Validation rejects non-positive or non-numeric values, and any config where yellow is not strictly below red.

When It Updates

• session_start — reload config, reconstruct assistant cost from branch history, paint the status bar
• turn_end — add the latest assistant cost and cache stats, refresh the status bar
• session_compact — reset running cost/cache totals and repaint from current context usage