---
title: "From Session Browser to Mission Control: Evolving a Developer Tool"
description: "How claude-view evolved from a simple JSONL viewer into a real-time multi-agent monitoring dashboard in 25 days."
date: 2026-02-19
author: claude-view team
---

claude-view started as a weekend project to browse Claude Code sessions. Twenty-five days later it was a real-time multi-agent monitoring dashboard. The evolution from session browser to Mission Control wasn't planned — each phase was driven by a pain point that made the previous version insufficient.

## Phase 1: Session browser (days 1-2)

The original problem was simple: Claude Code stores conversations as JSONL files in `~/.claude/projects/`, but there's no way to browse them. You can `cat` the files, but they're raw JSON with nested content blocks and base64-encoded images. We built a session list, a message viewer with syntax highlighting, and HTML export. That was v0.1.

The architecture was minimal — Rust reads JSONL files on startup, serves a React SPA from embedded static assets, exposes two API endpoints. No database, no indexing, no background processes.

## Phase 2: Search and analytics (days 3-8)

Once you have 200+ sessions, you need search. Substring matching on in-memory data worked for a week, then we hit sessions with 1,000+ messages and search took 800ms. We integrated Tantivy, a Rust full-text search engine (think Lucene but without the JVM), and got query times under 5ms.

Analytics came from the same data. Every assistant message includes token usage — `input_tokens`, `output_tokens`, `cache_read_input_tokens`, `cache_creation_input_tokens`. Aggregate those across sessions and you have cost tracking. Plot them over time and you have trend charts. The data was always there; we just started computing over it.

The architecture gained SQLite for persistent metadata and Tantivy for the search index. Both rebuild from JSONL source files on startup if the schema version changes.

## Phase 3: Git integration (days 9-14)

A natural question after browsing sessions: "What did this session actually produce?" We added git log scanning to link sessions with commits by timestamp correlation. If a commit happened during or shortly after a session in the same project directory, it's associated with that session.

This phase also added contribution analysis — what percentage of your git output involved AI assistance, broken down by project and time period. The data model expanded from "conversations" to "conversations + their real-world outputs."

## Phase 4: Live monitoring (days 15-22)

This was the inflection point. Everything before this was historical — browsing past sessions, analyzing completed work. Live monitoring meant watching active sessions in real time.

The technical jump was significant. We added:

- **Process discovery** — scanning the process table for running Claude Code instances, associating them with project directories via `lsof`
- **JSONL tail watching** — using `notify` (inotify/kqueue) to detect new messages as they're written
- **Server-Sent Events** — pushing session state updates to the browser in real time
- **Session state classification** — inferring whether each agent is autonomous, waiting for input, or done

The architecture went from request-response to event-driven. SSE streams replaced polling. A background task continuously monitors process liveness and file changes, broadcasting state transitions to connected clients.

## Phase 5: Plugin and relay (days 23-25)

Two extensions emerged from the monitoring work. The Claude Code plugin (`@claude-view/plugin`) exposes session data as MCP tools — so Claude itself can answer "what did I work on today?" by querying its own session history. The WebSocket relay enables the mobile app to receive live updates from the local server without port forwarding.

## The key inflection

When live monitoring became the primary use case, we moved Mission Control to the home page. Session history became a secondary view, accessible from the sidebar. This was a product decision driven by usage: we opened claude-view 10x more often to check on running agents than to browse past conversations.

## What the evolution taught us

Every architecture decision from Phase 1 became either a foundation or a liability in Phase 4. mmap-based JSONL parsing (foundation) — same code reads historical and live files. Embedded static assets (foundation) — one binary, no build step for users. No database (liability) — had to add SQLite when in-memory data didn't scale. No real-time layer (liability) — had to add SSE and background workers.

The lesson: if your tool reads data that changes over time, build the real-time path early. Retrofitting event-driven architecture onto a request-response system is possible but expensive. We did it in 7 days; starting with SSE from day 1 would have saved 3 of those days.
