Context Inspector

This extension adds the /context command which displays a map of the current session context. Gives a rough break up of what is taking up the context.

What it shows

The inspector is a read-only snapshot of the current Pi session. It groups the current state into sections:

• Overview — cwd, session file, session id, model, thinking level, usage
• System prompt & resources — custom prompt, appended prompt, context files, skills, tool snippets, fallback prompt
• Slash commands — registered commands
• Tool registry & active tools — all tools and which ones are active
• Session branch (raw entries) — the session branch history
• Resolved model context — the final message list after session resolution
• Request preview — a compact summary of the request that would be sent

Linting

Install dev dependencies in the package directory, then run:

npm run lint
npm run lint:watch
npm run check

These use TypeScript's compiler to surface type and syntax errors without emitting files.

Usage view

At the top, the inspector shows estimated context usage:

• a usage bar
• a colored 10×10 usage grid
• a category legend
• Reserved blocks at the end when compaction reserves tokens

The category colors are just visual helpers. They do not change behavior.

How it works

1. Cache prompt info

   • On before_agent_start, the extension stores the latest system prompt and prompt options.

2. Build a snapshot

   • buildSnapshot() gathers everything into one immutable object.
   • This keeps the UI stable while you move around inside it.

3. Estimate usage

   • estimateUsageCategories() approximates token usage from prompt resources, resolved messages, and compaction settings.
   • These numbers are estimates, not exact accounting.

4. Render lines

   • buildInspectorLines() turns the snapshot into plain text lines.
   • styleInspectorLines() adds the border and colors.

5. Interact

   • Arrow keys move between sections/items.
   • Enter or → expands a section.
   • ← or Esc collapses.
   • e exports the snapshot to .pi/context-snapshot.json.
   • q closes the inspector.

Notes

• The inspector only opens in an interactive UI session.
• It refuses to open while the current turn is still running.
• Export is also only available from an idle interactive session.