debugger

Dev-only observability for AI agent debugging. 4 languages, 28 frameworks, zero production footprint.

Agents when don't run the own servers don't have terminal context, to get information from browsers we often need MCP servers, and pasting information back to agents is a time consuming process. Debugger is aimed for you who don't want to run mcp servers and usually preferer running servers in separated terminals instead of bloating agent context with outputs, now agents can do all that and filter what they need to debug using proper filters.

Note: This is a preview feature currently under active development.

npm install -D @ephem-sh/debugger

debugger captures browser and server-side logs, errors, network requests, and application state from your running dev server. AI agents query this data through the dbg CLI.

dbg browser console           # browser console logs
dbg server console            # server console logs
dbg browser network           # fetch, xhr, websocket
dbg browser cookies           # document cookies
dbg browser storage           # localStorage + sessionStorage
dbg status                    # session info
dbg all --json                # everything as JSON

Supported frameworks

Node.js — @ephem-sh/debugger

Framework	Setup	Adapter
Next.js	2 files	@ephem-sh/debugger/nextjs
React + Vite	1 file	@ephem-sh/debugger/vite
Vue + Vite	1 file	@ephem-sh/debugger/vite
SvelteKit	2 files	@ephem-sh/debugger/vite + /vite/sveltekit
React Router v7	2 files	@ephem-sh/debugger/vite + /vite/react-router
Astro	2 files	@ephem-sh/debugger/vite + /vite/astro
Nuxt	2 files	@ephem-sh/debugger/vite + /nitro
Qwik	2 files	@ephem-sh/debugger/vite
TanStack Start	3 files	@ephem-sh/debugger/vite + /vite/tanstack-start
Waku	1 file	@ephem-sh/debugger/vite
Angular	2 files	@ephem-sh/debugger/angular
Express	1 line	@ephem-sh/debugger/express
Hono	1 line	@ephem-sh/debugger/hono
Elysia	1 line	@ephem-sh/debugger/elysia
Fastify	1 line	@ephem-sh/debugger/fastify
NestJS	2 lines	@ephem-sh/debugger/nest
AdonisJS	2 files	@ephem-sh/debugger/adonis
Nitro	2 files	@ephem-sh/debugger/vite + middleware

Go — ephem-debugger-go

Framework	Setup	Middleware
Gin	3 lines	middleware/gin
Echo	3 lines	middleware/echo
Chi	3 lines	middleware/chi

Python — ephem-debugger-py

Framework	Setup	Middleware
FastAPI	2 lines	ephem_debugger_py.middleware.fastapi
Flask	2 lines	ephem_debugger_py.middleware.flask
Django	1 line	ephem_debugger_py.middleware.django

Rust — ephem-debugger-rs

Framework	Setup	Feature
Axum	3 lines	axum
Actix-web	3 lines	actix
Rocket	3 lines	rocket
Poem	3 lines	poem

Quick start (Vite + React)

Add the plugin to your Vite config:

// vite.config.ts
import { debuggerPlugin } from '@ephem-sh/debugger/vite'

export default defineConfig({
  plugins: [react(), debuggerPlugin()],
})

Start your dev server, then query:

npx dbg status
npx dbg browser console

How it works

1. Server instrumentation patches console.* and starts an IPC bridge when your dev server boots.
2. Browser client (auto-injected IIFE) captures console, errors, network, cookies, storage, permissions, and quota.
3. CLI (dbg) queries the session over IPC and returns structured output.

All data lives in memory (ring buffers). Nothing is written to disk. Zero production footprint — all adapters no-op outside development.

Development

bun install                     # install deps
bun run build                   # build package
bun run typecheck               # typecheck
bun run examples                # list example apps
bun run install:example nextjs  # install example deps
bun run dev:example nextjs      # run example dev server

Documentation

• Getting started
• CLI reference
• Framework guides in docs/examples/

License

MIT