pi-lean

Compact TUI for the pi coding agent: collapse every tool call to a single line, shrink the user message to a tinted one-liner, strip the blank lines between blocks, and keep the agent's prose short and dense. Independent extensions in one package, plus a theme built for them.

▶ bash   git status
▶ read   compiler.go
▶ edit   parser.go (+8 -2)
▶ grep   SemanticEditProtocol

Install

pi install npm:@guygrigsby/pi-lean

lean-tools — one line per tool

pi's built-in tool blocks render a full colored shell (the green/red box). This strips the shell and folds each completed call to a single ▶ line: tool, target, and a minimal summary (edits show (+A -B), failures show why, everything else stays bare). Running calls stream live so you still see activity.

Control	Effect
ctrl+q	cycle folded → expanded → hidden
/tools [mode]	set folded | expanded | hidden directly (cycles with no arg)
ctrl+o	(built-in) expand a row's output
PI_LEAN_MODE	startup mode: folded (default) | expanded | hidden
PI_LEAN_SKIP	tools to force-skip, e.g. edit,write (default: none)

It takes over the built-in tool rendering (read, bash, edit, write, grep, find, ls) — but per tool, and only where nothing else got there first. Registration happens at session_start, after asking the live registry (pi.getAllTools) who owns each tool: one already registered by another extension is left to it, automatically. No coordination config, no conflict error.

The case this exists for is edits: folding a diff to one line hides the only part worth seeing. Turn on registerToolOverrides.edit and .write in pi-tool-display's config.json (its other entries false) and lean backs off those two: syntax-highlighted diffs with row fills and word-level emphasis for edits, one-line folds for everything else. Run without pi-tool-display and lean takes all seven. Deferred tools are also exempt from lean-anytool's fold, so the other renderer's row survives whole. See ADR 2.

PI_LEAN_SKIP remains as a manual override: named tools are never registered by lean, falling to whatever else claims them or pi's built-in rendering.

Expand is keyboard-driven (ctrl+q all rows, ctrl+o a row's output). Per-row click-to-expand isn't offered: pi never enables terminal mouse reporting and exposes no mouse events or row hit-testing to extensions, so clicks belong to your terminal (text selection), not pi. Clickable rows would need an upstream pi change.

lean-usermsg — thin user message

pi's default user message wraps its text in a Box with a hardcoded paddingY: 1 — a blank tinted line above and below, so a one-word message is three lines tall. This zeroes that padding: a single tinted line, no frame. It patches a pi core internal (UserMessageComponent.prototype.rebuild), guarded so a pi update degrades to the stock render instead of crashing.

Control	Effect
PI_LEAN_USERMSG	off → leave pi's padded default alone

Pairs with pi-tool-display's enableNativeUserMessageBox: false (drop its framed box) and a distinct userMessageBg in your theme for the tint.

lean-spacing — no blank lines between blocks

AssistantMessageComponent interleaves its content with Spacer(1) (one blank line) before the text, between each tool call, and around notices — the vertical gap between folded ▶ rows and around turns. There's no setting for it. This drops those spacers (the structural ones only; markdown paragraph breaks are untouched). Same guarded core patch as lean-usermsg.

Control	Effect
PI_LEAN_SPACING	off → leave pi's default spaced transcript alone

Maximally tight by design. If turns end up too cramped, set PI_LEAN_SPACING=off.

lean-prose — short, dense output

Appends a terseness layer to the system prompt: lead with the answer, cut preamble and filler, prefer a phrase to a sentence. Tone and length only — never trades away correctness or completeness of the work.

Control	Effect
/prose	toggle on/off (persists)
/prose on | /prose off	set directly
PI_LEAN_PROSE	startup default: on (default) | off

State persists to $PI_CODING_AGENT_DIR/lean-prose.json.

neutral-hue — a theme for this look

themes/neutral-hue.json, offered by the package and selected with "theme": "neutral-hue" in your settings or /settings.

Neutral dark grays for prose, hue only where it separates structure: purple keywords, blue functions, green strings, teal types, orange numbers, lavender inline code. Two tokens matter more than the rest once edits render as real diffs, since the diff renderer fills rows from them:

Token	Value	What it paints
toolSuccessBg	#1c3326	added-line background
toolErrorBg	#3a1f26	removed-line background

A theme that leaves those at the terminal background gets a diff with no fill.

Install

pi install /path/to/pi-extensions/lean

Then /reload or restart pi.

Test

npm test

Covers the pure line-formatting logic (extensions/lean-tools-core.mjs). The TUI rendering wiring is exercised by running pi.

Credit

lean-tools adapts the tool re-registration + renderShell: "self" approach from pi-foldable-tools (MIT, earendil-works), tightened from a 2-line card to a single line.