session-hygiene

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

🟢 session healthy
🟡 session growing
🔴 session critical

Health is based on:

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

The status can also append cache-rate info:

• Prompt cache hit rate as 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)
🟡 session growing · 98% cache

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