pi — UI layout and detection

Agent: pi (@earendil-works/pi-coding-agent). Version audited: 0.83.0 · Date: 2026-08-02 · Theme: rose-pine-moon.

All values below were captured live from a real PTY session (raw ANSI), not inferred.

Identity & rendering

Property	Value
Binary	`pi` (npm global; the executable on disk is the node interpreter)
Rendering engine	`@earendil-works/pi-tui` (own TUI lib — not Ink, not Bubble Tea)
Repaint style	Full-frame, wrapped in synchronized updates (`\033[?2026h` … `\033[?2026l`)
Screen clear	`\033[2J\033[H\033[3J` on startup repaint
Cursor positioning	Relative — `\033[3A` up / `\033[3B` down, then `\033[1G`, cursor hidden (`\033[?25l`)
Config dir	`~/.pi/agent/`
Sessions	`~/.pi/agent/sessions/<encoded-cwd>/<ISO-ts>_<uuid7>.jsonl`

Process identity gotcha. proc_pidpath() (macOS) and /proc/<pid>/comm (Linux) both return the node interpreter for a pi session, not pi. Foreground-process classification therefore falls back to argv[0] for known interpreters — see is_script_interpreter in pty.rs and read_process_argv0 in process_env.rs. Without that fallback pi is invisible as an agent.

Bottom zone

Four rows, in this order, present in every state:

────────────────────────────────────────────  separator, RGB(196,167,231)
<composer>                                    reverse-video cursor block + blanks
────────────────────────────────────────────  separator
~/Gits/personal/tuicommander (main)           cwd + branch, RGB(110,106,134)
↑1.3k ↓1.8k R15k W6.0k CH88.5% $0.104 3.4%/272k (auto)    (openai) gpt-5.6-sol • medium

No prompt glyph. The composer is a bare reverse-video cell (\033[7m \033[0m) followed by blanks. is_prompt_line matches nothing here — readiness cannot be prompt-based.
Status row is the reliable “this is a pi screen” marker: the context gauge N%/Nk plus the • model separator. See is_pi_status_row in pty.rs.

Working state

The composer row is replaced in place by an animated status row:

 ⠏ Working...

Spinner: braille ⠋⠙⠹⠸⠼⠴⠦⠧⠇⠏, RGB(196,167,231); label RGB(144,140,170).
Already matched by chrome::is_spinner_row (braille range U+2800–U+28FF).
Separators, cwd row and status row stay on screen unchanged for the whole turn.

detect_pi_screen_activity therefore reads: spinner in the footer → Working; otherwise, status row present → Ready; neither → Unknown.

OSC sequences

Sequence	Notes
`\033]8;;\007`	Emitted after nearly every row (hyperlink reset)
`\033]0;<title>\007`	Only with the `terminal-status-title` extension installed

The extension (~/.pi/agent/extensions/terminal-status-title.js) prefixes the title with a state glyph, repainted every 120ms while working:

Glyph	State	Source event
`○` (U+25CB)	idle	`session_start`
`⠋…⠏` braille	working	`agent_start`
`✓` (U+2713)	done	`agent_end`
`✗` (U+2717)	error	—

TUIC does not derive activity from this title: the screen adapter already owns the busy→idle transition, and a second path for the same transition is a race, not a safety net. The title only feeds the tab name, and cleanOscTitle strips the glyph and the | separator it sits on so every spinner frame collapses to one stable name (π | tuicommander).

Input

Property	Value
Submit	`Enter` (verified live: text + `\r` submits)
Newline	`shift+enter` / `ctrl+j`
Clear to line start	`ctrl+u` (`tui.editor.deleteToLineStart`)
Interrupt	`ctrl+c` (`app.clear`)

sendCommand’s agent path (Ctrl-U prefix, 50ms gap, separate \r) is correct for pi as-is — ctrl+u is a real binding, so the prefix is consumed rather than echoed.

Not yet observed

Permission/approval prompts, interactive menus (pi config), and the session picker (--resume) were not triggered during this audit. They are unaudited, not “absent” — trigger them before relying on any assumption about their chrome.