Session Explorer

Session Explorer provides deep-dive analysis of individual Claude Code sessions. It parses the raw .jsonl session log files that Claude Code writes during each conversation and produces rich HTML reports or serves an interactive browser for exploring multiple sessions.


session-explorer [sessionId] [options]

Modes

Session Explorer operates in two modes depending on whether a session ID is provided:

Browser Mode (no session ID)


session-explorer                    # Launch on default port 3456
session-explorer --port 8080        # Launch on custom port

Starts a local HTTP server that serves an interactive web application. The browser UI includes a sidebar listing all discoverable Claude sessions, and clicking a session loads its full analysis. This is the best way to explore sessions when you don’t know the exact session ID.

Report Mode (with session ID)


session-explorer <sessionId>                    # Generate HTML report (opened in browser)
session-explorer <sessionId> --json             # Output raw JSON analysis to stdout
session-explorer <sessionId> --out report.html  # Save HTML report to a specific file

Generates a detailed analysis of a single session. The session ID can be a full UUID or a unique prefix — it will be matched against all known session files.

Options

Option	Description
`--port <number>`	Port for the session browser server (default: 3456)
`--out <path>`	Custom output path for the HTML report
`--json`	Output raw analysis as JSON instead of HTML
`--help`	Show help message

Report Features

Each session report contains multiple analysis tabs:

Metrics Tab

Token usage — Input tokens, output tokens, and cache reads/writes broken down by role (user, assistant, system)
Cost breakdown — Estimated cost based on token counts and model pricing
Tool call distribution — Frequency and success rate of each tool used (Read, Edit, Write, Bash, Grep, Glob, etc.)
Model information — Which model was used and session duration

Timeline Tab

Full event timeline — Every request/response pair in chronological order with human-readable summaries
Tool call details — For each assistant turn, which tools were invoked and their arguments/results
Text content — User messages and assistant text responses rendered inline
Error tracking — Failed tool calls and error messages highlighted

Subagent Tracking

When a session spawns subagents (e.g., through the Agent tool), their events are merged into the main timeline with visual distinction. Per-subagent metrics (token usage, tool calls) are tracked and displayed separately, so you can see how much work each subagent performed relative to the parent session.

Session Discovery

Session Explorer looks for Claude session files in the standard Claude Code data directories:

~/.claude/projects/ — Project-scoped session files
~/.claude/sessions/ — Global session files (newer UUID-based format)

Each session is a .jsonl file containing one JSON object per line, representing the streaming events from a Claude conversation.

Relationship to Composer Report

The two reporting tools serve different purposes:

	`composer report`	`session-explorer`
Scope	All Claude sessions across a full composition (multiple steps)	Single Claude session in depth
Use case	”How much did this entire feature cost?"	"What exactly happened in the architect session?”
Aggregation	Sums tokens and costs across all steps	Detailed per-event breakdown within one session
Timeline	Step-level overview (which roles ran, in what order)	Event-level detail (every tool call, every message)
Access	By composer session ID	By Claude session ID

Use composer report when you want a high-level summary of an entire workflow’s resource usage. Use session-explorer when you need to understand what happened inside a specific Claude conversation — for example, to debug why a developer agent made certain decisions or to audit which files a reviewer examined.

Example Workflow


# See all composer sessions and generate an aggregate report
composer report
 
# Find the Claude session IDs from the report, then deep-dive into one
session-explorer 3458a9d0
 
# Or browse all sessions interactively
session-explorer