pi-statusbar

A configurable statusbar footer for the pi-coding-agent TUI. It shows context about your current session: the working directory, model and provider, thinking level, git status, token usage, context window, cache reads and writes, and running cost.

It's powered by powerline-style segments with a Catppuccin Mocha theme. You can reorder, remove, or add sections, change the divider between them, or swap the whole colour theme.

How it looks

The statusbar sits at the bottom of the pi TUI. Each section is a coloured segment separated by powerline chevrons (or rounded caps between certain sections). Sections appear from left to right in the order you've configured.

How it works

flowchart LR
    subgraph pi["pi-coding-agent"]
        TUI["TUI (Footer slot)"]
        API["Extension API"]
    end

    subgraph statusbar["pi-statusbar extension"]
        CONFIG["~/.pi/agent/statusbar.json"]
        REGISTRY["Section registry"]
        THEME["Catppuccin theme<br/>(or custom JSON)"]
        FOOTER["Footer component"]
    end

    subgraph segments["Built-in segments"]
        DIR["directory"]
        PROV["provider"]
        MODEL["model"]
        THINK["thinking"]
        GIT["git"]
        COST["cost"]
        CTX["context"]
        TOKENS["token-flow"]
        CACHE["cache"]
    end

    API -- session_start --> FOOTER
    FOOTER --> REGISTRY
    CONFIG --> FOOTER
    REGISTRY --> segments
    THEME --> FOOTER
    FOOTER -- render(width) --> TUI

On session_start, pi-statusbar registers a footer component with the pi TUI. Each render pass walks the configured section list, calls each section's render function with lazy accessors (no wasted computation for sections that never read the data), wraps the text in ANSI styling from the theme, and joins everything with powerline divider characters.

The git section runs a background poller — it checks git status every few seconds and caches the result so the render path doesn't block on a subprocess.

Install

pi-statusbar is available on npm. Install it using pi install:

pi install @kreeger/pi-statusbar

If you've cloned the repository locally, you can also install from the local path:

pi install /path/to/pi-statusbar

After installation, restart your pi session. The statusbar appears automatically — there's no activation step needed.

Verify it is installed

ls ~/.pi/agent/extensions/pi-statusbar/

You should see TypeScript source files. The pi agent loads extensions from this directory at startup.

Configuration

Section order

Create ~/.pi/agent/statusbar.json. The default configuration (used when this file doesn't exist) is:

{
  "divider": " | ",
  "sections": [
    "directory", "provider", "model", "thinking",
    "git", "cost", "context", "token-flow", "cache"
  ]
}

The divider field is the text inserted between sections when powerline glyphs aren't available (not typically visible in the TUI). The sections array lists the built-in segment IDs in display order. Remove any you don't want, or reorder them.

Custom themes

Add a themePath field pointing to a JSON file with ANSI escape sequences for foreground and background colours:

{
  "sections": ["directory", "git", "cost"],
  "themePath": "/home/you/.pi/themes/my-theme.json"
}

The theme file merges over the built-in Catppuccin theme. Each section can override foreground (fg) and background (bg) as raw SGR escape sequences. A defaultSection catches any section without its own entry. Here's an example theme file:

{
  "defaultSection": {
    "fg": "\u001b[38;2;147;153;178m",
    "bg": ""
  },
  "sections": {
    "directory": {
      "fg": "\u001b[38;2;55;55;75m",
      "bg": "\u001b[48;2;249;226;175m"
    },
    "git": {
      "fg": "\u001b[38;2;250;179;135m",
      "bg": "\u001b[48;2;55;55;75m"
    }
  }
}

Only the keys you provide are replaced. Sections not mentioned keep their Catppuccin defaults.

Built-in segments

ID	Shows
directory	Current working directory, abbreviated (e.g. ~/src/my-project becomes ~/s/my-project)
provider	Model provider name (e.g. anthropic, openai)
model	Model identifier, provider prefix stripped (e.g. claude-sonnet-4-20250514)
thinking	Current thinking level setting
git	Git branch, ahead/behind counts, and file change counts (+ added, ~ modified, - deleted, ? untracked)
cost	Running session cost
context	Context window usage percentage and total window size
token-flow	Input and output token counts for the session
cache	Cache reads and writes (prompt caching)

Writing custom segments

External extensions can register custom sections with pi-statusbar's SectionRegistry. The registry is available on the global scope at __piStatusbarRegistry. Call register() with an object that has an id and a render(ctx) function.

Here's a complete extension that adds a section showing the current time:

import type { ExtensionAPI } from "@earendil-works/pi-coding-agent";
import type { SectionAccessors } from "./types.js";

export default function (pi: ExtensionAPI) {
  pi.on("session_start", (_event, ctx) => {
    if (!ctx.hasUI) return;

    const registry = (globalThis as any).__piStatusbarRegistry;
    if (!registry) return;  // pi-statusbar not installed

    registry.register({
      id: "clock",
      render(ctx: SectionAccessors) {
        return new Date().toLocaleTimeString([], {
          hour: "2-digit",
          minute: "2-digit",
        });
      },
    });
  });
}

After installing this extension, add "clock" to the sections array in statusbar.json:

{
  "sections": ["directory", "clock", "git", "cost"]
}

How custom segment registration works

1. pi-statusbar creates a SectionRegistry on session start and exposes it as globalThis.__piStatusbarRegistry.
2. External extensions access the registry in their own session_start handler (which runs after pi-statusbar's).
3. register() accepts any object matching the StatusbarSection interface: { id: string; render(ctx: SectionAccessors): string | undefined }.
4. If your id matches a built-in section, yours replaces it.
5. Unknown IDs in statusbar.json are silently skipped, so you must list your custom ID in the sections array for it to appear.

Section accessors

The render function receives a SectionAccessors object. Each getter is lazy — it only computes when called, and caches the result for the current render pass. If your section doesn't call a getter, that data is never collected.

interface SectionAccessors {
  getCwd(): string;
  getModel(): StatusbarModel | undefined;
  getThinkingLevel(): string;
  getUsage(): StatusbarUsage;
  getContextUsage(): StatusbarContextUsage | undefined;
  getGit(): GitStatusSnapshot;
}

Type definitions

The pi-statusbar source includes full TypeScript types in types.ts. You can reference them from your extension by importing from the extension directory, or copy the types you need.

Development

Setup

Clone the repository and install dependencies:

git clone git@github.com:kreeger/pi-statusbar.git
cd pi-statusbar
npm install

Running tests

npm test

Tests live alongside source files (.test.ts). They run with Vitest. There are tests for the section registry, config parsing, theme loading, the ANSI styler, the git state poller, the format utilities, and the extension lifecycle.

Deploying your changes

The deploy script copies the source files (minus test files) to ~/.pi/agent/extensions/pi-statusbar/. Use it to push local changes into pi without publishing to npm:

npm run deploy

Restart your pi session to pick up changes.

Architecture notes

• index.ts — Extension entry point. Hooks into session lifecycle, wires up config, theme, registry, and git polling.
• config.ts — Reads statusbar.json from disk. Falls back to defaults when the file is missing or invalid.
• registry.ts — Holds the mapping of section IDs to render functions. External extensions push into this.
• footer.ts — Creates the TUI Component. Each render pass collects data lazily then delegates to the styler.
• styler.ts — Interface for all ANSI rendering. Keeps layout code free of escape codes.
• themes/ — Theme loading and the built-in Catppuccin theme.
• sections/ — Built-in section implementations.
• git/ — Asynchronous git status polling.
• format.ts — Shared number/string formatting utilities.

License

MIT