sessionlog:tokenusage

---
name: sessionlog:tokenusage
description: >
  This skill should be used when the user asks to "show token usage",
  "how many tokens", "token count", "token stats", "input output tokens",
  "API usage", "usage summary", "sessionlog tokenusage", "tokenusage",
  or wants to extract and report input/output token counts from
  Claude Code session logs.
disable-model-invocation: false
---

# Session Token Usage

Extract and report input/output token counts from Claude Code session logs.

## Steps

### 1. Identify session

```bash
project_dir="$HOME/.claude/projects/$(pwd | sed 's|/|-|g')"
current_session=$(ls -t "$project_dir"/*.jsonl 2>/dev/null | head -1)
session_id=$(basename "$current_session" .jsonl)
echo "Session: $session_id"
echo "Source: $current_session"
```

If the user specifies a session ID, use that instead of the most recent one.

### 2. Extract token usage

```bash
python3 -c "
import json, sys

log_file = sys.argv[1]

# Deduplicate by message ID — session logs may contain multiple
# JSONL lines per API call (streaming). Take the last usage block
# per unique message ID for accurate counts.
usage_by_msg = {}

with open(log_file) as f:
    for line in f:
        line = line.strip()
        if not line:
            continue
        try:
            obj = json.loads(line)
        except json.JSONDecodeError:
            continue
        msg = obj.get('message', {})
        msg_id = msg.get('id')
        usage = msg.get('usage')
        if msg_id and usage:
            usage_by_msg[msg_id] = usage

totals = {
    'input_tokens': 0,
    'output_tokens': 0,
    'cache_creation_input_tokens': 0,
    'cache_read_input_tokens': 0,
}

for usage in usage_by_msg.values():
    for key in totals:
        totals[key] += usage.get(key, 0)

msg_count = len(usage_by_msg)
total_input = totals['input_tokens'] + totals['cache_creation_input_tokens'] + totals['cache_read_input_tokens']
print(f'API calls:                   {msg_count:>12,}')
print(f'Input tokens:                {totals[\"input_tokens\"]:>12,}')
print(f'Output tokens:               {totals[\"output_tokens\"]:>12,}')
print(f'Cache creation input tokens: {totals[\"cache_creation_input_tokens\"]:>12,}')
print(f'Cache read input tokens:     {totals[\"cache_read_input_tokens\"]:>12,}')
print(f'Total input (all types):     {total_input:>12,}')
" "$current_session"
```

### 3. Report results

Present results as a clean table:

- **Session ID** — the UUID
- **API calls** — number of unique API calls with usage data
- **Input tokens** — non-cached input tokens
- **Output tokens** — tokens generated by the model
- **Cache creation tokens** — input tokens written to prompt cache
- **Cache read tokens** — input tokens served from prompt cache
- **Total input** — sum of all input token types