Inside Claude Code's Brain: Debugging Claude's Behavior with Log Analysis

Discover how to debug Claude Code's behavior using cclogviewer, a tool that analyzes session logs to reveal tool usage, errors, and token counts, enabling log-based improvement loops.

Overview

Live demo of cclogviewer — an open-source MCP server and CLI tool that reads Claude Code’s internal JSONL session logs and turns them into structured, queryable data: tool usage stats, session timelines, token counts, and error summaries. I’ll walk through how it works, how to set it up, and how I used it to analyze 650 automated Claude Code sessions to diagnose why skills only activate ~50% of the time and how to create a logs-based improvement loop for Claude Code Subagents.

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