Session Timer

Features

• Elapsed session time in HH:MM:SS format
• Real-time tokens per minute calculation
• Cost per hour estimation
• Session start time display
• Productivity metrics (tokens/min indicator)
• Color-coded efficiency ratings
• Persistent timing across statusline refreshes
• Pomodoro technique integration with break reminders

Use Cases

• Track billable hours for client work
• Monitor session productivity and efficiency
• Budget management for API cost control
• Time-boxed development sessions (Pomodoro technique)
• Performance benchmarking across different models
• Team time tracking for collaborative development sessions

Requirements

• Claude Code CLI installed and configured
• Bash shell available (bash 4.0+ recommended for pattern matching, arithmetic operations, and string manipulation)
• jq command-line JSON processor (jq 1.6+ recommended for safe extraction with // defaults)
• date command with epoch support (macOS: date -j, Linux: date -d) for timestamp parsing
• bc calculator (optional, for cost per hour calculation - script uses awk as fallback)
• Terminal with ANSI color code support (256-color mode recommended for color-coded productivity indicators)

Configuration

{
  "statusLine": {
    "type": "command",
    "command": "$CLAUDE_PROJECT_DIR/.claude/statuslines/session-timer-statusline.sh",
    "refreshInterval": 1000
  }
}

Examples

Enhanced Session Timer with Start Time Display

Extended version showing session start time and elapsed duration

#!/usr/bin/env bash

# Enhanced Session Timer with Start Time Display

export LC_NUMERIC=C

read -r input

model=$(echo "$input" | jq -r '.model.id // .model.display_name // "unknown"' | sed 's/claude-//')
tokens=$(echo "$input" | jq -r '.cost.total_lines_added // .session.totalTokens // 0')
cost=$(echo "$input" | jq -r '.cost.total_cost_usd // .session.estimatedCost // 0')
session_start=$(echo "$input" | jq -r '.session.startTime // ""')

# Detect OS for date command
if [[ "$OSTYPE" == "darwin"* ]]; then
  DATE_CMD="date -j"
  DATE_FORMAT="-f"
else
  DATE_CMD="date"
  DATE_FORMAT="-d"
fi

# Calculate session duration
if [ -n "$session_start" ]; then
  start_clean=$(echo "$session_start" | sed 's/\.\{0,1\}[0-9]\{0,3\}Z\{0,1\}$//' | sed 's/T/ /')

  if [[ "$OSTYPE" == "darwin"* ]]; then
    start_epoch=$(date -j -f "%Y-%m-%d %H:%M:%S" "$start_clean" "+%s" 2>/dev/null || echo "0")
    start_formatted=$(date -j -f "%Y-%m-%d %H:%M:%S" "$start_clean" "+%H:%M" 2>/dev/null || echo "")
  else
    start_epoch=$(date -d "$start_clean" "+%s" 2>/dev/null || echo "0")
    start_formatted=$(date -d "$start_clean" "+%H:%M" 2>/dev/null || echo "")
  fi

  current_epoch=$(date +%s 2>/dev/null || echo "0")

  if [ "$start_epoch" != "0" ] && [ "$current_epoch" != "0" ]; then
    duration=$((current_epoch - start_epoch))

    if [ $duration -lt 0 ]; then
      duration=0
    fi

    hours=$((duration / 3600))
    minutes=$(((duration % 3600) / 60))
    seconds=$((duration % 60))
    formatted_time=$(printf "%02d:%02d:%02d" $hours $minutes $seconds)

    if [ $duration -gt 0 ]; then
      tokens_per_min=$((tokens * 60 / duration))

      if [ $tokens_per_min -gt 500 ]; then
        prod_color="\033[32m"
        prod_indicator="🔥"
      elif [ $tokens_per_min -gt 200 ]; then
        prod_color="\033[33m"
        prod_indicator="⚡"
      else
        prod_color="\033[36m"
        prod_indicator="💭"
      fi
    else
      tokens_per_min=0
      prod_color="\033[36m"
      prod_indicator="💭"
    fi

    if command -v bc > /dev/null 2>&1 && [ $duration -gt 0 ]; then
      cost_per_hour=$(echo "scale=2; $cost * 3600 / $duration" | bc -l 2>/dev/null || echo "0.00")
    elif command -v awk > /dev/null 2>&1 && [ $duration -gt 0 ]; then
      cost_per_hour=$(awk "BEGIN {printf \"%.2f\", $cost * 3600 / $duration}" 2>/dev/null || echo "0.00")
    else
      cost_per_hour="0.00"
    fi
  else
    formatted_time="00:00:00"
    tokens_per_min=0
    cost_per_hour="0.00"
    prod_indicator="💭"
    prod_color="\033[36m"
    start_formatted=""
  fi
else
  formatted_time="00:00:00"
  tokens_per_min=0
  cost_per_hour="0.00"
  prod_indicator="💭"
  prod_color="\033[36m"
  start_formatted=""
fi

RESET="\033[0m"

# Build statusline with start time
if [ -n "$start_formatted" ]; then
  echo -e "\033[35m⏱  ${formatted_time}${RESET} (start: ${start_formatted}) │ \033[36m${model}${RESET} │ ${prod_color}${prod_indicator} ${tokens_per_min}/min${RESET} │ \033[33m\$${cost_per_hour}/hr${RESET}"
else
  echo -e "\033[35m⏱  ${formatted_time}${RESET} │ \033[36m${model}${RESET} │ ${prod_color}${prod_indicator} ${tokens_per_min}/min${RESET} │ \033[33m\$${cost_per_hour}/hr${RESET}"
fi

Session Timer with Pomodoro Alerts

Version with Pomodoro technique support (25-minute work intervals)

#!/usr/bin/env bash

# Session Timer with Pomodoro Alerts

export LC_NUMERIC=C

read -r input

model=$(echo "$input" | jq -r '.model.id // .model.display_name // "unknown"' | sed 's/claude-//')
tokens=$(echo "$input" | jq -r '.cost.total_lines_added // .session.totalTokens // 0')
cost=$(echo "$input" | jq -r '.cost.total_cost_usd // .session.estimatedCost // 0')
session_start=$(echo "$input" | jq -r '.session.startTime // ""')

# Pomodoro interval (25 minutes = 1500 seconds)
POMODORO_INTERVAL=${POMODORO_INTERVAL:-1500}

# Detect OS for date command
if [[ "$OSTYPE" == "darwin"* ]]; then
  DATE_CMD="date -j"
else
  DATE_CMD="date"
fi

# Calculate session duration
if [ -n "$session_start" ]; then
  start_clean=$(echo "$session_start" | sed 's/\.\{0,1\}[0-9]\{0,3\}Z\{0,1\}$//' | sed 's/T/ /')

  if [[ "$OSTYPE" == "darwin"* ]]; then
    start_epoch=$(date -j -f "%Y-%m-%d %H:%M:%S" "$start_clean" "+%s" 2>/dev/null || echo "0")
  else
    start_epoch=$(date -d "$start_clean" "+%s" 2>/dev/null || echo "0")
  fi

  current_epoch=$(date +%s 2>/dev/null || echo "0")

  if [ "$start_epoch" != "0" ] && [ "$current_epoch" != "0" ]; then
    duration=$((current_epoch - start_epoch))

    if [ $duration -lt 0 ]; then
      duration=0
    fi

    # Check Pomodoro interval
    pomodoro_count=$((duration / POMODORO_INTERVAL))
    pomodoro_remaining=$((POMODORO_INTERVAL - (duration % POMODORO_INTERVAL)))

    hours=$((duration / 3600))
    minutes=$(((duration % 3600) / 60))
    seconds=$((duration % 60))
    formatted_time=$(printf "%02d:%02d:%02d" $hours $minutes $seconds)

    if [ $duration -gt 0 ]; then
      tokens_per_min=$((tokens * 60 / duration))

      if [ $tokens_per_min -gt 500 ]; then
        prod_color="\033[32m"
        prod_indicator="🔥"
      elif [ $tokens_per_min -gt 200 ]; then
        prod_color="\033[33m"
        prod_indicator="⚡"
      else
        prod_color="\033[36m"
        prod_indicator="💭"
      fi
    else
      tokens_per_min=0
      prod_color="\033[36m"
      prod_indicator="💭"
    fi

    if command -v bc > /dev/null 2>&1 && [ $duration -gt 0 ]; then
      cost_per_hour=$(echo "scale=2; $cost * 3600 / $duration" | bc -l 2>/dev/null || echo "0.00")
    elif command -v awk > /dev/null 2>&1 && [ $duration -gt 0 ]; then
      cost_per_hour=$(awk "BEGIN {printf \"%.2f\", $cost * 3600 / $duration}" 2>/dev/null || echo "0.00")
    else
      cost_per_hour="0.00"
    fi

    # Pomodoro alert
    if [ $pomodoro_remaining -le 60 ] && [ $pomodoro_remaining -gt 0 ]; then
      pomodoro_alert="🍅 ${pomodoro_remaining}s"
      pomodoro_color="\033[33m"
    elif [ $pomodoro_count -gt 0 ]; then
      pomodoro_alert="🍅 +${pomodoro_count}"
      pomodoro_color="\033[32m"
    else
      pomodoro_alert=""
      pomodoro_color=""
    fi
  else
    formatted_time="00:00:00"
    tokens_per_min=0
    cost_per_hour="0.00"
    prod_indicator="💭"
    prod_color="\033[36m"
    pomodoro_alert=""
    pomodoro_color=""
  fi
else
  formatted_time="00:00:00"
  tokens_per_min=0
  cost_per_hour="0.00"
  prod_indicator="💭"
  prod_color="\033[36m"
  pomodoro_alert=""
  pomodoro_color=""
fi

RESET="\033[0m"

# Build statusline with Pomodoro alert
if [ -n "$pomodoro_alert" ]; then
  echo -e "\033[35m⏱  ${formatted_time}${RESET} │ ${pomodoro_color}${pomodoro_alert}${RESET} │ \033[36m${model}${RESET} │ ${prod_color}${prod_indicator} ${tokens_per_min}/min${RESET} │ \033[33m\$${cost_per_hour}/hr${RESET}"
else
  echo -e "\033[35m⏱  ${formatted_time}${RESET} │ \033[36m${model}${RESET} │ ${prod_color}${prod_indicator} ${tokens_per_min}/min${RESET} │ \033[33m\$${cost_per_hour}/hr${RESET}"
fi

Session Timer Installation Example

Complete setup script with OS detection and date command verification

#!/bin/bash
# Installation script for Session Timer Statusline

# Check for jq (required for JSON parsing)
if ! command -v jq &> /dev/null; then
    echo "Installing jq for JSON parsing..."
    if [[ "$OSTYPE" == "darwin"* ]]; then
        brew install jq
    elif [[ "$OSTYPE" == "linux-gnu"* ]]; then
        sudo apt-get install -y jq || sudo yum install -y jq
    else
        echo "Please install jq manually: https://stedolan.github.io/jq/"
    fi
fi

# Check for bc (optional, for cost calculations)
if ! command -v bc &> /dev/null; then
    echo "Installing bc calculator (optional, for cost calculations)..."
    if [[ "$OSTYPE" == "darwin"* ]]; then
        brew install bc
    elif [[ "$OSTYPE" == "linux-gnu"* ]]; then
        sudo apt-get install -y bc || sudo yum install -y bc
    else
        echo "Note: bc is optional - script will use awk as fallback"
    fi
fi

# Check for awk (usually pre-installed)
if ! command -v awk &> /dev/null; then
    echo "Warning: awk command not found - cost calculations may not work"
    echo "Install awk: macOS (pre-installed), Linux (sudo apt-get install gawk or sudo yum install gawk)"
else
    echo "awk command available"
fi

# Test date command for OS compatibility
if [[ "$OSTYPE" == "darwin"* ]]; then
    if date -j -f "%Y-%m-%d %H:%M:%S" "2024-01-01 12:00:00" "+%s" &> /dev/null; then
        echo "macOS date command working: $(date -j -f '%Y-%m-%d %H:%M:%S' '2024-01-01 12:00:00' '+%s')"
    else
        echo "Warning: macOS date command test failed"
    fi
else
    if date -d "2024-01-01 12:00:00" "+%s" &> /dev/null; then
        echo "Linux date command working: $(date -d '2024-01-01 12:00:00' '+%s')"
    else
        echo "Warning: Linux date command test failed"
    fi
fi

# Test bc calculator (if available)
if command -v bc &> /dev/null; then
    if echo "scale=2; 0.05 * 3600 / 1800" | bc -l 2>/dev/null | grep -q "0.10"; then
        echo "bc calculator working: $(echo 'scale=2; 0.05 * 3600 / 1800' | bc -l)"
    else
        echo "Warning: bc calculator test failed"
    fi
fi

# Test awk for cost calculation
if command -v awk > /dev/null 2>&1; then
    test_cost=$(awk "BEGIN {printf \"%.2f\", 0.05 * 3600 / 1800}" 2>/dev/null)
    if [ "$test_cost" = "0.10" ]; then
        echo "awk cost calculation working: $test_cost"
    else
        echo "Warning: awk cost calculation test failed"
    fi
fi

# Test emoji support
if echo -e '⏱ 🔥 ⚡ 💭 🍅' &> /dev/null; then
    echo "Emoji characters supported: ⏱ 🔥 ⚡ 💭 🍅"
else
    echo "Warning: Emoji characters may not display correctly"
fi

# Create statuslines directory
mkdir -p .claude/statuslines

cat > .claude/statuslines/session-timer-statusline.sh << 'SCRIPT_EOF'
#!/usr/bin/env bash

# Session Timer Statusline for Claude Code
# Tracks session duration and productivity metrics

export LC_NUMERIC=C

read -r input

model=$(echo "$input" | jq -r '.model.id // .model.display_name // "unknown"' | sed 's/claude-//')
tokens=$(echo "$input" | jq -r '.cost.total_lines_added // .session.totalTokens // 0')
cost=$(echo "$input" | jq -r '.cost.total_cost_usd // .session.estimatedCost // 0')
session_start=$(echo "$input" | jq -r '.session.startTime // ""')

if [[ "$OSTYPE" == "darwin"* ]]; then
  DATE_CMD="date -j"
else
  DATE_CMD="date"
fi

if [ -n "$session_start" ]; then
  start_clean=$(echo "$session_start" | sed 's/\.\{0,1\}[0-9]\{0,3\}Z\{0,1\}$//' | sed 's/T/ /')

  if [[ "$OSTYPE" == "darwin"* ]]; then
    start_epoch=$(date -j -f "%Y-%m-%d %H:%M:%S" "$start_clean" "+%s" 2>/dev/null || echo "0")
  else
    start_epoch=$(date -d "$start_clean" "+%s" 2>/dev/null || echo "0")
  fi

  current_epoch=$(date +%s 2>/dev/null || echo "0")

  if [ "$start_epoch" != "0" ] && [ "$current_epoch" != "0" ]; then
    duration=$((current_epoch - start_epoch))

    if [ $duration -lt 0 ]; then
      duration=0
    fi

    hours=$((duration / 3600))
    minutes=$(((duration % 3600) / 60))
    seconds=$((duration % 60))
    formatted_time=$(printf "%02d:%02d:%02d" $hours $minutes $seconds)

    if [ $duration -gt 0 ]; then
      tokens_per_min=$((tokens * 60 / duration))

      if [ $tokens_per_min -gt 500 ]; then
        prod_color="\033[32m"
        prod_indicator="🔥"
      elif [ $tokens_per_min -gt 200 ]; then
        prod_color="\033[33m"
        prod_indicator="⚡"
      else
        prod_color="\033[36m"
        prod_indicator="💭"
      fi
    else
      tokens_per_min=0
      prod_color="\033[36m"
      prod_indicator="💭"
    fi

    if command -v bc > /dev/null 2>&1 && [ $duration -gt 0 ]; then
      cost_per_hour=$(echo "scale=2; $cost * 3600 / $duration" | bc -l 2>/dev/null || echo "0.00")
    elif command -v awk > /dev/null 2>&1 && [ $duration -gt 0 ]; then
      cost_per_hour=$(awk "BEGIN {printf \"%.2f\", $cost * 3600 / $duration}" 2>/dev/null || echo "0.00")
    else
      cost_per_hour="0.00"
    fi
  else
    formatted_time="00:00:00"
    tokens_per_min=0
    cost_per_hour="0.00"
    prod_indicator="💭"
    prod_color="\033[36m"
  fi
else
  formatted_time="00:00:00"
  tokens_per_min=0
  cost_per_hour="0.00"
  prod_indicator="💭"
  prod_color="\033[36m"
fi

RESET="\033[0m"

echo -e "\033[35m⏱  ${formatted_time}${RESET} │ \033[36m${model}${RESET} │ ${prod_color}${prod_indicator} ${tokens_per_min}/min${RESET} │ \033[33m\$${cost_per_hour}/hr${RESET}"
SCRIPT_EOF

chmod +x .claude/statuslines/session-timer-statusline.sh

# Add to settings.json
if [ ! -f .claude/settings.json ]; then
    echo '{"statusLine":{"type":"command","command":"$CLAUDE_PROJECT_DIR/.claude/statuslines/session-timer-statusline.sh","refreshInterval":1000}}' > .claude/settings.json
else
    jq '.statusLine = {"type":"command","command":"$CLAUDE_PROJECT_DIR/.claude/statuslines/session-timer-statusline.sh","refreshInterval":1000}' .claude/settings.json > .claude/settings.json.tmp
    mv .claude/settings.json.tmp .claude/settings.json
fi

echo "Session Timer Statusline installed successfully!"
echo "Note: Ensure LC_NUMERIC=C is set for correct decimal formatting"
echo "Note: Script detects OS automatically (macOS uses 'date -j', Linux uses 'date -d')"
echo "Test timer: Verify session.startTime is provided by Claude Code in JSON input"

Troubleshooting

Timer showing 00:00:00 or not incrementing

Ensure Claude Code is providing session.startTime in JSON. Check with: echo '$input' | jq '.session.startTime'. May require Claude Code update. Verify date command works: macOS (date -j -f '%Y-%m-%d %H:%M:%S' '2024-01-01 12:00:00' '+%s'), Linux (date -d '2024-01-01 12:00:00' '+%s'). Test timestamp parsing: start_clean=$(echo '$session_start' | sed 's/.{0,1}[0-9]{0,3}Z{0,1}$//' | sed 's/T/ /'). Check epoch calculation: current_epoch=$(date +%s) (should return current Unix timestamp).

date command error: illegal time format

macOS uses 'date -j -f', Linux uses 'date -d'. Script detects OS automatically using OSTYPE. For macOS: date -j -f '%Y-%m-%d %H:%M:%S' '2024-01-01 12:00:00' '+%s'. For Linux: date -d '2024-01-01 12:00:00' '+%s'. Verify OS detection: echo $OSTYPE (should be 'darwin*' for macOS, 'linux-gnu*' for Linux). Check timestamp format: session.startTime should be ISO 8601 (e.g., '2024-01-01T12:00:00' or '2024-01-01T12:00:00.123Z'). Script cleans timestamp: removes milliseconds and 'Z' suffix, replaces 'T' with space.

bc: command not found

Install bc calculator: macOS (brew install bc), Linux (sudo apt-get install bc or sudo yum install bc). Verify installation: command -v bc (should return path). Test bc: echo 'scale=2; 0.05 * 3600 / 1800' | bc -l (should return 0.10). Script has awk fallback: If bc unavailable, script uses awk for cost per hour calculation. Verify awk: command -v awk (should return path). Check both: Script tries bc first, then awk as fallback. Both methods should produce same result.

Tokens per minute showing unrealistic values

This is normal at session start. Metric stabilizes after 2-3 minutes of usage. Very high values indicate batch processing. Calculation: tokensper_min = tokens * 60 / duration. If duration is very small (< 60 seconds), tokensper_min can be very high. Wait for session to run longer (2-3 minutes) for accurate rate. Check tokens value: echo '$input' | jq '.cost.total_lines_added' (should return number). Check duration: echo $duration (should be seconds since session start). Verify calculation: tokens_per_min=$((tokens * 60 / duration)).

Cost per hour showing 0.00 or incorrect value

Check cost value: echo '$input' | jq '.cost.total_cost_usd' (should return decimal like 0.05). If zero, check alternative field: echo '$input' | jq '.session.estimatedCost'. Verify duration is greater than 0: echo $duration (should be > 0). Check calculation: cost*per_hour = cost * 3600 / duration. Test with bc: echo 'scale=2; 0.05 _ 3600 / 1800' | bc -l (should return 0.10). Test with awk: awk 'BEGIN {printf "%.2f", 0.05 * 3600 / 1800}' (should return 0.10). If both fail, check that bc or awk is installed.

Productivity indicators not changing colors

Verify tokens_per_min calculation: echo $tokens_per_min (should be number). Check thresholds: > 500 (🔥 green), > 200 (⚡ yellow), else (💭 cyan). Test comparison: if [ 600 -gt 500 ]; then echo "High productivity"; fi (should output). Verify color codes: Green (\033[32m), Yellow (\033[33m), Cyan (\033[36m). Test color: echo -e '\033[32mGreen\033[0m' (should display green text). Check RESET code: echo -e '\033[0m' (should reset colors). If colors not working, terminal may not support ANSI colors.

Negative duration or timer counting backwards

Check epoch calculation: start_epoch and current_epoch should be valid Unix timestamps. Verify: date +%s (should return current timestamp). Check timestamp parsing: start_clean should be valid date string. Test: if [["$OSTYPE" == "darwin"*]]; then date -j -f '%Y-%m-%d %H:%M:%S' '2024-01-01 12:00:00' '+%s'; else date -d '2024-01-01 12:00:00' '+%s'; fi. Script has protection: if [ $duration -lt 0 ]; then duration=0; fi. If still negative, check system clock: date (should show correct time). Verify session.startTime is not in future: Compare with current time.

Model name showing as 'unknown' or incorrect

Check model extraction: echo '$input' | jq '.model.id' (should return model ID like 'claude-opus-4-1'). Check alternative: echo '$input' | jq '.model.display_name' (should return display name like 'Opus'). Script uses: model=$(echo '$input' | jq -r '.model.id // .model.display_name // "unknown"'). Verify sed replacement: echo 'claude-opus-4-1' | sed 's/claude-//' (should return 'opus-4-1'). If model is 'unknown', check JSON structure: echo '$input' | jq .model (should show model object with id or display_name).