Minimal Claude Code statusline with context window warning

statusline.sh

#!/usr/bin/env bash

# Status line script for Claude Code
# Displays: Branch, Model, Cost, Duration, Lines changed
# Location: ~/.claude/scripts/statusline.sh
#
# Installation: ~/.claude/settings.json
# "statusLine": {
#   "type": "command",
#   "command": "~/.claude/scripts/statusline.sh"
# }
#
# Flags:
#   --preview  Use hardcoded JSON for quick testing

# Parse flags
PREVIEW=0
for arg in "$@"; do
  case "$arg" in
    --preview)
      PREVIEW=1
      ;;
  esac
done

# Check if jq is installed
if ! command -v jq >/dev/null 2>&1; then
  echo "Error: jq is required but not installed. Please install jq first." >&2
  exit 1
fi

# Read JSON input
if [ "$PREVIEW" -eq 1 ]; then
  input=$(cat <<EOF
{
  "hook_event_name": "Status",
  "session_id": "abc123...",
  "transcript_path": "/path/to/transcript.json",
  "cwd": "/current/working/directory",
  "model": {
    "id": "claude-opus-4-1",
    "display_name": "Opus"
  },
  "workspace": {
    "current_dir": "/current/working/directory",
    "project_dir": "/original/project/directory"
  },
  "version": "1.0.80",
  "output_style": {
    "name": "default"
  },
  "cost": {
    "total_cost_usd": 0.01234,
    "total_duration_ms": 45000,
    "total_api_duration_ms": 2300,
    "total_lines_added": 156,
    "total_lines_removed": 23
  },
  "context_window": {
    "total_input_tokens": 15234,
    "total_output_tokens": 4521,
    "context_window_size": 200000,
    "used_percentage": 42.5,
    "remaining_percentage": 57.5,
    "current_usage": {
      "input_tokens": 8500,
      "output_tokens": 1200,
      "cache_creation_input_tokens": 5000,
      "cache_read_input_tokens": 2000
    }
  }
}
EOF
)
else
  input=$(cat)
fi

# Validate JSON input
if [ -z "$input" ]; then
  echo "Error: No JSON input received from Claude Code." >&2
  exit 1
fi

# Dump JSON to file for debugging
echo "$input" > /tmp/claude-statusline-input.json

# Extract data from JSON
cost=$(echo "$input" | jq -r '.cost.total_cost_usd // 0' 2>/dev/null)
total_input=$(echo "$input" | jq -r '.context_window.total_input_tokens // 0' 2>/dev/null)
total_output=$(echo "$input" | jq -r '.context_window.total_output_tokens // 0' 2>/dev/null)
context_percentage=$(echo "$input" | jq -r '.context_window.used_percentage // 0' 2>/dev/null)
model_name=$(echo "$input" | jq -r '.model.display_name // ""' 2>/dev/null)
model_id=$(echo "$input" | jq -r '.model.id // ""' 2>/dev/null)
workspace_dir=$(echo "$input" | jq -r '.workspace.current_dir // .workspace.project_dir // ""' 2>/dev/null)

# Validate critical values were parsed successfully
if [ -z "$cost" ] || [ "$cost" = "null" ]; then
  echo "Error: Failed to parse session data. Invalid or malformed JSON input." >&2
  exit 1
fi

# Get current git branch (use workspace directory if available)
if [ -n "$workspace_dir" ] && [ -d "$workspace_dir" ]; then
  branch=$(git -C "$workspace_dir" rev-parse --abbrev-ref HEAD 2>/dev/null || echo "no-branch")
else
  branch=$(git rev-parse --abbrev-ref HEAD 2>/dev/null || echo "no-branch")
fi

# Format tokens with k/M suffix
format_tokens_short() {
  local num="$1"
  num=${num//[^0-9]/}
  if [ -z "$num" ]; then
    echo "0"
    return
  fi

  if [ "$num" -ge 1000000 ]; then
    awk "BEGIN {printf \"%.0fM\", $num / 1000000}"
  elif [ "$num" -ge 1000 ]; then
    awk "BEGIN {printf \"%.0fk\", $num / 1000}"
  else
    echo "$num"
  fi
}

# Calculate context tokens from percentage (actual context window usage)
context_window_size=$(echo "$input" | jq -r '.context_window.context_window_size // 200000' 2>/dev/null)
context_tokens=$(awk "BEGIN {printf \"%.0f\", $context_percentage * $context_window_size / 100}")
context_display=$(format_tokens_short "$context_tokens")

# Calculate session total (all input/output tokens consumed)
session_total=$((total_input + total_output))
session_display=$(format_tokens_short "$session_total")

# Prepare model display string (show name if available, fallback to ID)
if [ -z "$model_name" ] || [ "$model_name" = "null" ]; then
  model_display="$model_id"
else
  model_display="$model_name"
fi


# Convert percentage to integer
context_percent_int=$(awk "BEGIN {printf \"%.0f\", $context_percentage}")

# Choose context emoji based on token count
if [ "$context_tokens" -lt 30000 ]; then
  context_emoji="😊"
elif [ "$context_tokens" -lt 70000 ]; then
  context_emoji="🤓"
elif [ "$context_tokens" -lt 100000 ]; then
  context_emoji="😟"
else
  context_emoji="😠"
fi

# Build and print status line
LC_ALL=C printf "🌿 \033[1;92m%s\033[0m | 🤖 \033[1;96m%b\033[0m | %s Context: \033[1;97m%s\033[0m (\033[1;94m%d%%\033[0m) | 💰 Session: \033[1;97m%s\033[0m (\033[1;93m\$%.4f\033[0m)" \
  "$branch" \
  "$model_display" \
  "$context_emoji" \
  "$context_display" \
  "$context_percent_int" \
  "$session_display" \
  "$cost"