claude-code-statusline: Instructions file for Claude Code

CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

Project Overview

Rust binary statusline for Claude Code CLI displaying (in order):

• Directory (📁)
• Git branch (🌿) when in a Git repository
• File changes (✏️) when present
• Model name (🤖)
• Context usage visualization with progress bar (📊)
• Cost tracking (💰) when present and enabled

Primary file: src/main.rs Language: Rust 1.96, edition 2024 Binary name: statusline

Development Commands

Testing

# Run all tests (unit + integration)
cargo test

# Run only unit tests (inline #[cfg(test)] in src/*.rs)
cargo test --bins

# Run integration tests (builds the binary first)
cargo test --test integration

# Manual testing
echo '{"model":{"display_name":"Test"},"workspace":{"current_dir":"/tmp"},"context_window":{"context_window_size":200000,"remaining_percentage":72,"current_usage":{"input_tokens":1000,"output_tokens":0,"cache_creation_input_tokens":0,"cache_read_input_tokens":0}},"cost":{"total_cost_usd":0.42}}' | cargo run --quiet

Building

# Dev build
cargo build

# Release build
cargo build --release

# Dev install (build debug binary and copy manually)
cargo build && cp target/debug/statusline ~/.claude/statusline

Linting

cargo clippy --all-targets -- -D warnings

Architecture

Data Flow

JSON stdin → input.rs (parse) → config.rs (load TOML) → git.rs (git status) → components.rs (build) → render.rs (assemble) → stdout

Module Map

Module	Responsibility
src/main.rs	Entry point: --print-defaults, --version, --configure-settings flags or parse→build→render pipeline
src/configure.rs	--configure-settings <settings_path> <command_path> — reads/merges/writes ~/.claude/settings.json atomically
src/input.rs	JSON parsing via serde_json; validate_directory() for security
src/config.rs	TOML config loading; BarStyle/Language/Theme enums with fallback warnings; print_defaults()
src/git.rs	Single git status --porcelain=v2 --branch --untracked-files=all call; parse_porcelain_v2()
src/components.rs	All component builders (build_model, build_directory, build_git, build_files, build_context, build_cost), each taking a &Palette; build_all() orchestrator
src/render.rs	ANSI color constants, Palette/build_palette() (theme → semantic colors), BAR_FILLED/BAR_EMPTY/BAR_WIDTH, assemble()
src/debug_log.rs	Debug-only (#[cfg(debug_assertions)]): appends raw stdin JSON to ~/.claude/statusline-debug.log for troubleshooting
tests/integration.rs	End-to-end tests spawning the compiled binary with fixture JSON