Claude Code /stats

[skytect]

Was curious how /stats works in Claude Code so I got Claude to reverse engineer it (on v2.0.69). Thought I'd share it here.

● Summary: How /stats Works in Claude Code

  Location and Definition

  The /stats command is defined in the bundled cli.js at approximately line 4383 (minified/bundled):

  {
    type: "local-jsx",
    name: "stats",
    description: "Show your Claude Code usage statistics and activity",
    isEnabled: () => true,
    isHidden: false,
    async call(A, Q, B) {
      return createElement(StatsComponent, { onClose: A })
    }
  }

  Data Source

  Stats are collected from .jsonl session log files stored in:
  - Base path: ~/.claude/projects/
  - Structure: Each project gets a directory named with dashes replacing slashes (e.g., -home-ivan-Documents-tasks)
  - Session files: UUID-named .jsonl files like 0746bf28-45ff-4d23-8f44-592da6a7026d.jsonl

  Data Collection (kTA function)

  The stats processor reads each session file and extracts:

  1. From each session:
    - Session ID, duration, message count, timestamp
    - Tool call counts
    - Hourly activity distribution
  2. From assistant messages (type: "assistant"):
    - input_tokens
    - output_tokens
    - cache_read_input_tokens
    - cache_creation_input_tokens
    - web_search_requests (from server_tool_use)
    - Model name

  Stats Object Structure (eX5 empty template)

  {
    totalSessions: 0,
    totalMessages: 0,
    totalDays: 0,
    activeDays: 0,
    streaks: {
      currentStreak: 0,
      longestStreak: 0,
      currentStreakStart: null,
      longestStreakStart: null,
      longestStreakEnd: null
    },
    dailyActivity: [],        // GitHub-style contribution data
    dailyModelTokens: [],     // Token usage by model per day
    longestSession: null,
    modelUsage: {},           // Per-model token counts
    firstSessionDate: null,
    lastSessionDate: null,
    peakActivityDay: null,
    peakActivityHour: null
  }

  Per-Model Usage Tracking (modelUsage)

  {
    inputTokens: 0,
    outputTokens: 0,
    cacheReadInputTokens: 0,
    cacheCreationInputTokens: 0,
    webSearchRequests: 0,
    costUSD: 0,
    contextWindow: 0
  }

  UI Tabs

  The stats UI has 2 main tabs:
  1. Overview - Summary stats including:
    - Total sessions count
    - Longest session duration
    - Current/longest streaks (days)
    - Activity contribution graph (GitHub-style)
  2. Models - Per-model token usage breakdown

  Caching

  Stats are cached to avoid reprocessing all historical data:
  - Cache file: stats-cache.json in Claude config dir
  - Cache version: 1 (versioned for compatibility)
  - Incremental updates: Only processes new data since lastComputedDate

  Key Functions

  | Function | Purpose                                       |
  |----------|-----------------------------------------------|
  | Ag2()    | Main loader - orchestrates data collection    |
  | eh2()    | Gets list of session .jsonl files             |
  | kTA()    | Processes sessions and extracts stats         |
  | _Y0()    | Reads stats cache                             |
  | QQA()    | Saves stats cache                             |
  | sX5()    | Merges historical stats with today's activity |
  | SY0()    | Renders activity contribution graph           |

● That's the complete reverse engineering of /stats. The command reads session logs from ~/.claude/projects/*/, parses the JSONL files to extract message counts, token usage per model, session durations, and displays it in an interactive UI with Overview and Models tabs plus a GitHub-style activity contribution graph.