Pi Thinking Steps

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Why this exists

Pi already exposes provider thinking, but raw reasoning streams are hard to scan in a real terminal. Pi Thinking Steps keeps the source text faithful while making it dramatically easier to follow:

• less visual noise while a model is still thinking
• more structure when you want the reasoning flow at a glance
• cleaner full-detail rendering when you need to inspect the exact text
• no invented reasoning, synthetic logic, or browser-style chrome

The goal is simple: preserve meaning, improve readability, and stay native to Pi's TUI.

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Visual tour

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What you get

• Three focused modes — collapsed, summary, expanded
• Terminal-first rendering — width-aware, ANSI-safe, and live-update friendly
• Faithful parsing — deterministic step derivation and restrained summarization
• Markdown-aware output — headings, bullets, ordered lists, code spans, and emphasis render cleanly
• Scoped persistence — session, project, and global defaults with predictable restore precedence
• Patch safety — isolated, reversible, reference-counted runtime patching
• Regression coverage — parser, renderer, lifecycle, compatibility, and metadata checks

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The three modes

Mode	Best for	Behavior
collapsed	Live active thinking	Shows a single compact line for the highest-signal active step
summary	Flow at a glance	Shows one summarized line per derived step in chronological order
expanded	Deep inspection	Shows the full step text in a cleaner, structured terminal layout

collapsed

Use it when you want the smallest possible thinking footprint while the model is still working.

summary

Use it when you want to understand the reasoning path quickly without reading the full transcript.

expanded

Use it when you want the whole text, but formatted for a terminal instead of dumped as a raw stream.

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Control surface

Action	Control
Cycle thinking view	Alt+T
Choose a mode interactively	/thinking-steps
Set session mode	/thinking-steps collapsed / summary / expanded
Save a project default	/thinking-steps project <mode>
Save a global default	/thinking-steps global <mode>
Clear a project default	/thinking-steps project clear
Clear a global default	/thinking-steps global clear

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Persistence and restore precedence

Mode restoration follows this order:

1. session history
2. project default from .pi/thinking-steps.json
3. global default from ~/.pi/agent/state/thinking-steps.json
4. built-in default summary

Use plain /thinking-steps <mode> when the choice should stay local to the current session. Use project or global when you want future sessions to inherit that choice automatically.

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Example output

Summary

┆ Thinking Steps · Summary
├─ ◫ Inspect the current renderer implementation.
├─ ↔ Compare how visibility toggling works.
└─ ✓ Verify the refresh path after mode changes.

Expanded

┆ Thinking Steps · Expanded
├─ ◫ Inspect the current renderer implementation.
│  Inspect the current renderer implementation.
├─ ↔ Compare how visibility toggling works.
│  Compare how visibility toggling works.
└─ ✓ Verify the refresh path after mode changes.
   Verify the refresh path after mode changes.

Collapsed

│ Thinking ✓ Verify the refresh path after mode changes. ·

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Rendering behavior

Pi Thinking Steps is built to improve readability without changing meaning.

Parsing and step derivation

The parser uses deterministic rules to keep step boundaries believable and stable. Examples:

• standalone markdown headings stay attached to the body they introduce
• list items split into separate steps when that improves scanability
• blank-line continuation paragraphs stay attached to the correct list item
• standalone concluding prose after a list stays separate from the final list item
• provider-hidden reasoning remains clearly marked as hidden

Display formatting

The renderer normalizes markdown-like content for terminal display:

• headings render as headings instead of leaking raw # markers
• unordered list items render with clean bullets
• ordered and lettered list markers are preserved
• backticks render as code-styled inline text
• emphasis markers render cleanly instead of leaking raw *...* / _..._
• raw control sequences from model output are stripped before rendering

Terminal-first constraints

This extension is designed for a real terminal, not a browser UI. That means:

• width-aware wrapping matters
• ANSI-safe rendering matters
• over-decoration is intentionally avoided in the live TUI
• the output should remain readable in narrow layouts

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Technical approach

Pi currently exposes only a minimal public hook for built-in thinking rendering: setHiddenThinkingLabel.

To deliver a full three-mode thinking view, Pi Thinking Steps patches Pi's internal AssistantMessageComponent at runtime and replaces the default visible thinking rendering path with a custom renderer.

That patch layer is:

• isolated — patching lives in internal-patch.ts
• reversible — cleanup restores original methods
• reference-counted — multiple retain/release paths are handled safely
• guarded — compatibility checks fail loudly when Pi internals drift
• tested — integration and regression coverage protects the patch lifecycle

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Compatibility contract

This extension intentionally depends on Pi's current internal TUI implementation.

Today, the patch relies on these internal modules in @mariozechner/pi-coding-agent:

• dist/modes/interactive/components/assistant-message.js
• dist/modes/interactive/theme/theme.js

That means:

• upstream Pi internal changes can break the patch layer
• Pi upgrades should be treated as deliberate compatibility work
• the pinned Pi package versions and package-lock.json matter
• npm test is part of the maintenance contract, not an optional extra
• if patch install fails during session_start, the current session stays on Pi's native thinking renderer and live mode switching is disabled for that degraded session
• project/global default saves and clears remain available during a degraded session, but they apply only to future compatible sessions
• if session_shutdown is missed, a later extension shutdown can still release the retained process-global patch regardless of cwd

The current package uses Pi package version 0.69.0 as runtime dependencies in package.json, and compatibility-sensitive upgrades must update package-lock.json in the same change.

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Quick start

From the repository root:

pi -e ./index.ts

The package entry point is already configured in package.json:

"pi": {
  "extensions": ["./index.ts"]
}

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Development

Install dependencies:

npm install

Run the full validation suite:

npm test

Typecheck only:

npm run build

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Published package contents

The package ships:

• README.md
• LICENSE
• the extension TypeScript sources
• the README SVG assets under assets/

That keeps the GitHub README and the published package presentation aligned.

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Project structure

• index.ts — extension entry point, commands, shortcut, lifecycle hooks
• internal-patch.ts — Pi runtime patching and cleanup
• parse.ts — thinking-step splitting, summaries, role inference, mode parsing
• persistence.ts — project/global mode preference storage
• render.ts — collapsed, summary, and expanded terminal rendering
• state.ts — shared mode, active-thinking state, patch lifecycle state
• types.ts — shared contracts
• test/thinking-steps.test.ts — unit and integration coverage
• test/summarizer-challenger.test.ts — focused summarizer-regression coverage

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Design principles

1. Readable over flashy

   • The goal is clarity, not decoration.

2. Faithful over clever

   • The renderer should not invent meaning the source text does not support.

3. Terminal-native over web-like

   • The output should feel right in a terminal first.

4. Small surface area

   • Parsing, rendering, state, and patching stay deliberately separated.

5. Strict validation

   • Changes should be backed by tests, especially around patch lifecycle and compatibility.

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Versioning

For the canonical package version, see package.json. For release points, use the repository tags.

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License

This project is released under the MIT License.