Monocle Studio

Monocle gives you full observability in production — traces, logs, exceptions, performance. But what about when you're developing locally?

Monocle Studio is a lightweight companion built for local development. One command, and you get a focused dashboard showing what's happening inside your app as you code. No setup, no external services — it just works.

Think of it as browser DevTools, but for your backend. Every HTTP request, every database query, every log — visible in real-time as you develop.

See the full trace waterfall for every request
Track outgoing HTTP calls to external APIs
Spot slow queries before they become production issues
Browse structured logs with stack traces and JSON attributes
Catch exceptions before they ever reach your users
Connect your AI coding assistant via MCP to query your traces

How it works

Your app uses the same Monocle agent as in production. In development, the agent automatically sends telemetry to Monocle Studio instead of the cloud. Studio receives it, stores it locally, and serves a dashboard — all on a single port (localhost:4200). Data persists between restarts so you can review past sessions.

Features

Traces & Requests

HTTP requests with full span waterfall, timing, and attributes

Logs

Structured logs with severity filtering, JSON viewer, and stack traces

Exceptions

Exceptions with stack traces, grouped by type

Database Queries

SQL queries with duration and statement preview

External Calls

Outgoing HTTP calls to external APIs with domain, status, and duration

Background Jobs

Job execution, queue name, duration, and success/failure tracking

CLI Commands

Traces for CLI scripts and scheduled tasks with custom spans

MCP Server

Let Claude Code or Cursor query your local traces and logs

Real-time

New data appears instantly — no manual refresh needed

Quick start

Install the packages

Terminal

npm install -D @monocle.sh/studio @monocle.sh/cli

Start Monocle Studio
Terminal
```
monocle studio dev
```
This starts the Studio server on http://localhost:4200.
Start your app
Terminal
```
node ace serve --hmr
```
Make some requests, then open http://localhost:4200 to see your traces, logs, and exceptions.
Teach your coding agent about Studio (optional)
Terminal
```
monocle studio install-agents
```
This appends a managed Monocle Studio block to AGENTS.md or CLAUDE.md so your agents know about Monocle Studio and how to use it.

No extra configuration is needed. The config/monocle.ts generated by the AdonisJS agent sets dev: process.env.NODE_ENV === 'development', which is the case during node ace serve. In dev mode, the agent sends data to Monocle Studio instead of the cloud.

CLI options

Terminal

monocle studio dev                     # Start on default port 4200
monocle studio dev --port 3000         # Custom port
monocle studio dev --host localhost    # Bind to localhost only
monocle studio dev --open              # Open browser automatically
monocle studio dev --clean             # Clear all stored data before starting
monocle studio dev --db-path ./my.db   # Custom database path

CLI commands

You can also query Studio data directly from your terminal without opening the browser. Fetch traces, logs, and errors with monocle studio traces, monocle studio logs, and monocle studio errors. See the CLI reference for all options.

Desktop app

Prefer a native app over a terminal command? Monocle Studio is also available as a standalone desktop application for macOS, Linux, and Windows — with system tray support and auto-updates.

Data storage

Monocle Studio stores data locally at ~/.config/monocle/studio.db. Data persists between restarts. Use monocle studio dev --clean to start fresh.