@tylerho/pi-collapsed-previews

Collapses hidden thinking blocks and edit-tool diffs to one-line summaries via runtime prototype patches on pi's TUI.

Install

pi install npm:@tylerho/pi-collapsed-previews

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Prototype: This package patches pi internals and may break with pi version updates. Pin your pi version and expect to update it when pi changes.

Collapsed Previews

TUI niceties for collapsed UI states: hidden thinking blocks show a snippet of the reasoning instead of a bare label, and edit tool diffs are collapsed to their header plus a +added -removed line-count summary. Both are runtime prototype patches on pi's own component classes — no dist files are modified.

Key concepts

• Prototype patching, not wrapping. The extension imports AssistantMessageComponent and ToolExecutionComponent from @earendil-works/pi-coding-agent and monkey-patches their prototypes. The package re-exports the same class objects and extensions share pi's module instance, so the patches affect pi's UI directly. Done at module import time (top-level side effects), not inside the exported init function.
• PATCHED marker prevents stacking. Each patch checks a Symbol.for("pi-collapsed-previews.patched") flag on the prototype before wrapping, and sets it after. Symbol.for survives /reload in-process, so handlers are never double-wrapped.
• Thinking snippets (patch on updateContent). The wrapper calls the original updateContent, then — only when hideThinkingBlock is on — groups the content's consecutive thinking blocks into "runs" (mirroring how pi renders consecutive thinking blocks under one collapsed label; runs are joined, whitespace-collapsed, trimmed), and for each run appends · <first 160 chars>… (ctrl+t) to the matching hidden-state label Text child. Label children are identified by their full text being exactly hiddenThinkingLabel (ANSI-stripped) — the only Text children whose entire content is the label; Markdown blocks hold longer prose. The label itself is set to 💭 thinking on session_start via ctx.ui.setHiddenThinkingLabel(...) so the match target is the extension's own label (pi's default is Thinking...).
• Edit-diff collapse (patch on updateDisplay). The wrapper calls the original updateDisplay, then — only when toolName === "edit", the component is not already expanded, and the call-renderer's preview has no error (errors stay visible) — removes all body children of the call-renderer (the diff lines, produced by pi's renderDiff) and rewrites the header to … · +N -M diff (ctrl+o). +/- counts come from counting diff lines starting with +/- in the stripped body text. Ctrl+O still expands the full diff like any other tool output.
• Lifecycle. The patches are installed once when the module loads; the only per-session work is re-asserting the thinking label on session_start (sessions are the unit where the hidden-label UI state lives).

API

The extension exposes no tools, no commands, no shortcuts, no config files — it is entirely passive UI behavior. The full surface:

Default export (extension entry)

export default function (pi: ExtensionAPI) — the standard extension init function. Registers the single event handler below.

Events

Event	Handler
session_start	Calls ctx.ui.setHiddenThinkingLabel("💭 thinking") (THINKING_LABEL). Sets the collapsed-thinking label that the updateContent patch matches against and annotates. Without this, the patch would match pi's default Thinking... label — the extension works either way, but the emoji label is the intended look.

Module-level side effects (installed at import, before the init function runs)

• patchAssistantMessage() — wraps AssistantMessageComponent.prototype.updateContent; appends reasoning snippets to hidden thinking labels. Constants: THINKING_LABEL = "💭 thinking", SNIPPET_MAX = 160 (chars per snippet, ellipsis appended when truncated). Rewritten label format: 💭 thinking · <snippet> (ctrl+t).
• patchToolExecution() — wraps ToolExecutionComponent.prototype.updateDisplay; collapses edit diffs. Rewritten header format: <header> · +<added> -<removed> diff (ctrl+o); stats omitted when the diff has no +/- lines.

Both are no-ops if the prototype is already marked patched.

Examples

• Hidden thinking shows a taste. With thinking blocks hidden (Ctrl+T), a reasoning-heavy answer renders 💭 thinking · The user wants me to refactor the auth middleware — let me check the current test cov… (ctrl+t) — enough context to follow the agent's reasoning without expanding, Ctrl+T for the full block.
• edit diffs stop dominating the scrollback. After an edit tool call, the diff body is replaced by the header line Edit: src/foo.ts · +12 -3 diff (ctrl+o). Ctrl+O expands the full diff inline; errors in the edit preview are never collapsed (kept fully visible).
• Survives /reload. Reloading extensions does not stack handlers — the Symbol.for marker keeps exactly one patch active.