⚡ Electron Debug MCP

Debug Electron apps from Cursor & Claude with real DevTools superpowers.
_{Model Context Protocol server · Chrome DevTools Protocol · start / attach / screenshot / console / DOM / UI automation / tracing}

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🌟 Overview

Electron Debug MCP is a local MCP server that gives AI coding agents eyes, hands, and Chrome DevTools inside your Electron app.

Instead of guessing from source alone, the agent can:

🎯 Goal	🛠️ How
Boot your app under a debugger	start_app with --remote-debugging-port
Hook an app you already launched	attach · attach_by_pid · find_apps · discover_apps
See the UI	screenshot / save_screenshot (full page or element clip via selector)
Read renderer failures	get_console_messages (level: "error") + exceptions
Stream console live	set_console_live → MCP log notifications
Inspect markup	get_dom / query_selector
Run JS in the page	evaluate
Run JS in main	start_app({ inspectMain: true }) → evaluate_main
Cookies & web storage	get_cookies / set_cookie · get_storage / set_storage
Watch network	get_network_log
Drive the UI	wait_for → type_text / press_key → click → navigate
Perf deep-dive	start_tracing → reproduce → stop_tracing (open in chrome://tracing)
One-shot health check	diagnose
Full DevTools power	cdp_command (Domain.method)

It speaks MCP over stdio (Cursor / Claude Desktop friendly), bridges to Chrome DevTools Protocol, buffers console + network on monitored page targets, and keeps stdout clean (all server logs go to stderr).

👤 Who it’s for

• 🧑‍💻 Cursor / Claude users pair-programming on Electron desktop apps
• 🐛 Maintainers tired of “white screen / silent exception” bugs agents can’t see
• 🧰 Tooling authors who need a stdio MCP ↔ CDP bridge for Electron/Chromium

💬 Example things you can ask the agent

“Start D:/apps/my-app on port 9222 and tell me if the renderer threw on boot.”
“Find my running Electron app, attach by PID, screenshot #sidebar, and dump localStorage.”
“Type into #email, press Enter, wait for Welcome, then list console errors.”
“Start a CDP trace, click through settings, stop tracing, and save the JSON.”
“Diagnose why this Electron window is blank.”

📊 At a glance

Aspect	Details
🔌 Transport	MCP stdio JSON-RPC
🧬 Debug bridge	Chrome DevTools Protocol (Runtime · Page · Network · Debugger · Input · Log · Tracing)
🚀 App control	Spawn Electron or attach by port / PID / process scan
📦 Surface area	36 tools · 6 resources · 3 prompts · logging + resource list-changed
🖥️ Platforms	Windows · macOS · Linux (CI: Xvfb + no-sandbox)
📦 Requires	Node ≥ 18, npm, one-time Electron binary download
🛡️ Safety	Optional ELECTRON_MCP_ALLOWED_ROOTS; attach sessions detach-only on stop
✅ Verify	npm test → unit + full MCP↔Electron smoke

✅ Status

• 🟢 Ready for local agent-driven Electron debugging
• 🟢 E2E smoke: start → UI/automation → storage/cookies → tracing → find/attach-by-pid → stop
• 🟢 Windows binary repair: scripts/fix-electron.cmd when npm blocks postinstall
• 🟢 v1.5.0 — element screenshots, cookies/storage, tracing, attach-by-pid

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📖 Table of contents

• Overview
• Why this exists
• Feature tour
• 60-second quick start
• Cursor & Claude Desktop setup
• How it works
• Complete tools cheatsheet
• Tools reference (all options)
• Resources
• Prompts
• Usage examples
• Configuration
• npm scripts
• Testing
• Project layout
• Security
• Troubleshooting
• Contributing
• License

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✨ Why this exists

Electron bugs are often invisible to coding agents:

😣 Pain	🙈 What agents usually see	👁️ What this server adds
Blank / white window	Source files only	Live screenshot + DOM (+ element clip)
Silent renderer crash	Nothing	Console + exception buffer (+ live stream)
Failed API calls	Guesswork	Network event log
Wrong route / URL	Unknown	page_info / evaluate
UI not responding	Can't interact	click / type_text / press_key / wait_for
Auth / state bugs	Blind	cookies + localStorage/sessionStorage
Perf jank	Guesswork	CDP tracing export
App already running	Manual port hunt	find_apps / attach_by_pid
Need DevTools power	Manual only	Full cdp_command escape hatch

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🚀 Feature tour

🔌 Lifecycle ▶️ start_app — launch with remote debugging (+ optional inspectMain) 🔗 attach — connect to an existing debug port 🆔 attach_by_pid — resolve port from process argv 🧭 find_apps — list Electron PIDs + debug ports 🔎 discover_apps — scan local CDP ports ⏹️ stop_app — kill owned / detach attached 📋 list_apps — sessions, ports, buffer counts 🩺 diagnose — port health + recent errors	🔍 Inspection 📸 screenshot / 💾 save_screenshot — full page or selector clip 🌳 get_dom / query_selector 🧮 evaluate / evaluate_main 🍪 get_cookies / set_cookie 🗄️ get_storage / set_storage 🧾 get_console_messages — log/warn/error/exceptions 🌐 get_network_log — request/response/fail 📜 get_logs — Electron stdout/stderr 🎯 list_targets / page_info
🖱️ Interaction 🧭 navigate + load wait ⏳ wait_for — selector / hidden / enabled / count / text / URL / console 🖱️ click left/right/middle ⌨️ type_text (+ clear / Enter) · press_key (+ modifiers) 🔄 reload · ⏸️ pause · ▶️ resume 🧹 clear_buffers	🧠 Agent UX & power 📝 MCP handshake instructions 💬 Prompts: blank window · exceptions · UI smoke 🏷️ Target roles: page / worker / browser / main 🔔 set_console_live + resource list-changed 📈 start_tracing / stop_tracing 🛡️ stderr-only diagnostics (stdio-safe) 🧰 cdp_command for any DevTools method

⚡ 60-second quick start

git clone https://github.com/amafjarkasi/electron-mcp-server.git
cd electron-mcp-server
npm install
npm run ensure-electron
npm run build
npm test

🪟 Windows binary missing?

If npm warns about allowScripts / Electron postinstall:

.\scripts\fix-electron.cmd

That reinstalls Electron, extracts electron.exe with system tar, then runs tests.

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🖥️ Cursor & Claude Desktop setup

Cursor

1. npm run build
2. Open Cursor → MCP settings
3. Add (use your absolute path):

Windows

{
  "mcpServers": {
    "electron-debug": {
      "command": "node",
      "args": ["D:/GH/electron-mcp-server/build/index.js"]
    }
  }
}

macOS / Linux

{
  "mcpServers": {
    "electron-debug": {
      "command": "node",
      "args": ["/Users/you/code/electron-mcp-server/build/index.js"],
      "env": {
        "ELECTRON_MCP_NO_SANDBOX": "1"
      }
    }
  }
}

4. Restart Cursor
5. Confirm tools: start_app, attach, find_apps, screenshot, get_console_messages, click, start_tracing, …

📄 Template: examples/cursor-mcp.json

Claude Desktop

Same mcpServers block in claude_desktop_config.json, pointing at build/index.js.

⚠️ Don’t run node build/index.js in a normal terminal for daily use — it waits on stdio for an MCP client. Let Cursor/Claude spawn it.

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🧩 How it works

┌──────────────────────────┐
│  Cursor / Claude / MCP   │
│  client (agent)          │
└────────────┬─────────────┘
             │ stdio JSON-RPC
             ▼
┌──────────────────────────┐
│  Electron Debug MCP      │
│  🛠️ tools (36)           │
│  📡 resources            │
│  💬 prompts              │
│  📣 logging / list-changed│
└────────────┬─────────────┘
             │ spawn / attach / PID resolve
             │ CDP WebSocket
             ▼
┌──────────────────────────┐
│  Electron application    │
│  --remote-debugging-port │
│  Runtime·Page·Network·…  │
│  optional --inspect (main)│
└──────────────────────────┘

After start_app / attach / attach_by_pid, page targets get Runtime / Log / Network / Page enabled so console + network events keep buffering between tool calls.

Finding a running app

1. find_apps — OS process scan (Electron PIDs + --remote-debugging-port from argv)
2. discover_apps — HTTP probe of local CDP ports (/json/version, /json/list)
3. attach / attach_by_pid — open a managed session (detach-only on stop_app)

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🗂️ Complete tools cheatsheet

Category	Tools
🚀 Lifecycle	start_app · attach · attach_by_pid · find_apps · discover_apps · stop_app · list_apps · diagnose
🔍 Inspect	screenshot · save_screenshot · get_dom · query_selector · evaluate · evaluate_main · get_cookies · set_cookie · get_storage · set_storage · get_console_messages · get_network_log · get_logs · list_targets · page_info
🖱️ Interact	navigate · wait_for · click · type_text · press_key · reload · pause · resume · clear_buffers · set_console_live
🧰 Power	start_tracing · stop_tracing · cdp_command

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🛠️ Tools reference (all options)

All APIs below are MCP tools. Schemas match the live Zod definitions in src/index.ts.

🚀 Lifecycle

start_app

Launch Electron with remote debugging.

Param	Type	Req	Default	Description
appPath	string	✅	—	App directory or main script
debugPort	int 1024–65535	❌	random 9222–9999	CDP port
extraArgs	string[]	❌	[]	Extra CLI flags
inspectMain	bool	❌	false	Pass --inspect=0 so main appears as a node target for evaluate_main

Auto flags: --remote-debugging-port, --enable-logging, --disable-gpu, and --no-sandbox when ELECTRON_MCP_NO_SANDBOX=1 / CI=true / no DISPLAY.

Returns: id, pid, debugPort, targets, attached: false, …

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attach

Param	Type	Req	Description
debugPort	int	✅	Existing DevTools port
name	string	❌	Friendly session name

stop_app on attached sessions detaches only (does not kill the external app).

---

attach_by_pid

Attach by OS process id. Resolves --remote-debugging-port from the process command line (Linux/macOS/ps, Windows PowerShell). Falls back to listening sockets owned by the PID on Linux when needed.

Param	Type	Req	Description
pid	int	✅	Electron main process id
name	string	❌	Friendly session name

Tip: Prefer the main process PID from find_apps (helpers with --type=renderer / gpu-process are filtered unless they expose a debug port).

---

find_apps

List running Electron-like processes.

Returns: { apps: [{ pid, command, debugPort?, inspectPort?, likelyElectron }], count }

Use this when you launched the app yourself and don’t remember the port.

---

discover_apps

Param	Type	Default
startPort	int	9222
endPort	int	9235

HTTP-probes each port for Chromium/Electron DevTools (/json/version + /json/list).

---

stop_app — { processId }

list_apps — no params

diagnose — optional { processId } (omit = all sessions)

diagnose reports port reachability, target role counts, recent console errors, and monitoring state.

---

🔍 Inspection

screenshot / save_screenshot

Param	Type	Default	Description
processId	string ✅	—	Session id
targetId	string	first page	CDP page target
format	png | jpeg	png	Image format
quality	int 0–100	—	JPEG only
selector	string	—	Element clip — capture only that node’s bounding box
path	string ✅ (save_screenshot)	—	File path to write

screenshot returns MCP image content (+ JSON meta including clip when used).
save_screenshot writes bytes to disk and returns { path, bytes, mimeType, clip? }.

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get_dom — { processId, selector?, targetId? }

query_selector — { processId, selector, targetId?, limit?=20 }

evaluate

Param	Type	Default
processId	string ✅	—
expression	string ✅	—
targetId	string	auto
role	page | worker | browser | any	page
returnByValue	bool	true

evaluate_main

Evaluate in the Electron main/node CDP target.

Param	Type	Default
processId	string ✅	—
expression	string ✅	—
targetId	string	auto-pick node/main
returnByValue	bool	true

Requires a node-like target — start with inspectMain: true, or pass an explicit targetId from list_targets.

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get_cookies

Param	Type	Description
processId	string ✅	—
urls	string[]	Optional URL filter
targetId	string	Page target

set_cookie

Param	Type	Description
processId	string ✅	—
name / value	string ✅	Cookie pair
url / domain	string	One required (defaults url to location.href when possible)
path	string	Cookie path
secure / httpOnly	bool	Flags
sameSite	Strict | Lax | None	SameSite
expires	number	Unix seconds
targetId	string	Page target

Note: Chromium often rejects cookies on file:// pages — use an http(s) URL or pass an explicit url/domain.

---

get_storage / set_storage

Param	Type	Default	Description
processId	string ✅	—	—
kind	localStorage | sessionStorage	localStorage	Store
entries	Record<string,string> ✅ (set)	—	Keys to write
clear	bool (set)	false	Clear store before write
targetId	string	—	Page target

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get_console_messages — { processId, tail?, level? }

get_network_log — { processId, tail? }

get_logs — { processId, tail? }

list_targets — { processId? }

page_info — { processId, targetId? } → url / title / readyState / userAgent

Console capture includes console.*, CDP Log entries, and Runtime.exceptionThrown.

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🖱️ Interaction & control

navigate — { processId, url, targetId?, waitUntilLoad?=true, timeoutMs?=15000 }

wait_for

Provide at least one condition:

Param	Meaning
selector	Element must exist
hidden	Element absent or not visible
enabled	Element exists and is not disabled
countSelector + minCount	querySelectorAll length ≥ min
text	document.body.innerText includes
urlIncludes	location.href includes
consoleIncludes	Buffered console text includes
timeoutMs	Default 10000 (max 120000)
screenshotOnTimeout	Save a PNG under the OS temp dir on failure
targetId	Page target

click — { processId, selector, targetId?, button?=left }

type_text — { processId, text, selector?, clear?, pressEnter?, targetId? }

press_key

Param	Type	Description
processId	string ✅	—
key	string ✅	e.g. Enter, Escape, Tab, ArrowDown, a
selector	string	Focus/click before keypress
modifiers	Alt | Control | Meta | Shift[]	Chord modifiers
repeat	int 1–50	Repeat count
targetId	string	Page target

set_console_live — { enabled }

Errors/asserts always emit MCP logs. When enabled, log/info/warn/debug also stream live.

reload — { processId, targetId?, ignoreCache?=false }

pause / resume — { processId, targetId? }

clear_buffers — { processId, console?=true, network?=true, logs?=false }

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🧰 Power / tracing

start_tracing

Param	Type	Description
processId	string ✅	—
categories	string	Comma-separated CDP categories (default: timeline + v8 profiler set)
targetId	string	Page target

Only one active trace per process session.

stop_tracing

Param	Type	Description
processId	string ✅	—
path	string	Output JSON path (default: OS temp dir)

Returns: { path, eventCount, elapsedMs, targetId, … }
Open the file in Chrome’s chrome://tracing (or Perfetto UI).

cdp_command — { processId, method:"Domain.method", targetId?, params? }

Escape hatch for any DevTools method not wrapped above.

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📡 Resources (read-only)

URI	MIME	Description
electron://info	JSON	Managed processes overview
electron://targets	JSON	All CDP targets
electron://process/{id}	JSON	Process details + webContents + recent errors
electron://logs/{id}	text	stdout/stderr capture
electron://console/{id}	JSON	Buffered console / exceptions
electron://cdp/{processId}/{targetId}	JSON	Target metadata

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💬 Prompts

Prompt	Args	Use when
debug_blank_window	processId	White/blank window
find_renderer_exception	processId	Hunting console/exceptions
ui_smoke_check	processId, selector	Wait → interact → verify

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📚 Usage examples

1️⃣ Start app → read title

// tool: start_app
{
  "appPath": "D:/apps/my-electron-app",
  "debugPort": 9222,
  "extraArgs": ["--no-sandbox"]
}

// tool: evaluate
{
  "processId": "electron-1710000000000",
  "expression": "document.title"
}

2️⃣ Attach to a running app (port)

electron . --remote-debugging-port=9222

// tool: attach
{ "debugPort": 9222, "name": "my-app" }

3️⃣ Find by PID → attach

// tool: find_apps
{}

// tool: attach_by_pid
{ "pid": 43210, "name": "my-app" }

4️⃣ Catch console errors (+ live stream)

// tool: set_console_live
{ "enabled": true }

// tool: get_console_messages
{
  "processId": "electron-1710000000000",
  "level": "error",
  "tail": 50
}

Also: resource electron://console/{processId}

5️⃣ Screenshot — full page, file, or element

// tool: screenshot
{ "processId": "electron-…", "format": "png" }

// tool: save_screenshot
{
  "processId": "electron-…",
  "path": "D:/tmp/app.png",
  "format": "png"
}

// tool: save_screenshot (element clip)
{
  "processId": "electron-…",
  "path": "D:/tmp/sidebar.png",
  "selector": "#sidebar"
}

6️⃣ UI automation flow

// wait_for
{ "processId": "electron-…", "selector": "#email", "timeoutMs": 8000 }

// type_text
{
  "processId": "electron-…",
  "selector": "#email",
  "text": "[email protected]",
  "clear": true
}

// press_key
{ "processId": "electron-…", "key": "Enter" }

// click
{ "processId": "electron-…", "selector": "button[type=submit]" }

// wait_for (richer conditions)
{
  "processId": "electron-…",
  "text": "Welcome",
  "timeoutMs": 8000,
  "screenshotOnTimeout": true
}

// wait_for enabled / count / hidden
{ "processId": "electron-…", "enabled": "#submit" }

{
  "processId": "electron-…",
  "countSelector": ".row",
  "minCount": 3
}

{ "processId": "electron-…", "hidden": ".spinner" }

7️⃣ Cookies & storage

// set_storage
{
  "processId": "electron-…",
  "kind": "localStorage",
  "clear": true,
  "entries": { "theme": "dark", "onboardingDone": "1" }
}

// get_storage
{ "processId": "electron-…", "kind": "localStorage" }

// set_cookie
{
  "processId": "electron-…",
  "name": "session",
  "value": "abc",
  "url": "https://app.local/"
}

// get_cookies
{ "processId": "electron-…", "urls": ["https://app.local/"] }

8️⃣ Main-process evaluate

// start_app with inspectMain
{
  "appPath": "D:/apps/my-electron-app",
  "debugPort": 9222,
  "inspectMain": true
}

// evaluate_main
{
  "processId": "electron-…",
  "expression": "process.versions.electron"
}

9️⃣ Performance tracing

// start_tracing
{ "processId": "electron-…" }

…reproduce the slow interaction (click / navigate / wait_for)…

// stop_tracing
{
  "processId": "electron-…",
  "path": "D:/tmp/app-trace.json"
}

Open app-trace.json in chrome://tracing.

🔟 Diagnose a sick session

// tool: diagnose
{ "processId": "electron-1710000000000" }

1️⃣1️⃣ Navigate + page info

// navigate
{
  "processId": "electron-…",
  "url": "file:///path/to/renderer/settings.html",
  "waitUntilLoad": true
}

// page_info
{ "processId": "electron-…" }

1️⃣2️⃣ Raw CDP escape hatch

// cdp_command
{
  "processId": "electron-…",
  "method": "Page.captureScreenshot",
  "params": { "format": "png", "fromSurface": true }
}

1️⃣3️⃣ Recommended agent loop

find_apps / discover_apps / start_app / attach / attach_by_pid
    → diagnose
    → set_console_live(true)   # optional
    → get_console_messages(level="error")
    → screenshot / save_screenshot(selector?)
    → wait_for (if UI)
    → click / type_text / press_key / evaluate / get_dom
    → get_storage / get_cookies   # if state matters
    → start_tracing … stop_tracing   # if perf
    → stop_app

---

🔐 Configuration

Environment variables

Variable	Purpose
ELECTRON_PATH	Force a specific Electron binary
ELECTRON_MCP_NO_SANDBOX=1	Always pass --no-sandbox
ELECTRON_MCP_ALLOWED_ROOTS	; / | allowlist for start_app paths
ELECTRON_MIRROR	Download mirror for Electron zips
ELECTRON_SKIP_BINARY_DOWNLOAD	Cleared by ensure-electron so download still runs
ELECTRON_CACHE / electron_config_cache	Zip cache directory
CI=true	Enables no-sandbox auto flag
unset DISPLAY (Linux)	Enables no-sandbox auto flag

Path allowlist example

$env:ELECTRON_MCP_ALLOWED_ROOTS="D:\apps;D:\GH"

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📜 npm scripts

Script	Does
npm run ensure-electron	Download/repair Electron binary
npm run fix-electron	Alias of ensure-electron
npm run build	Compile TS → build/
npm start	Run MCP server (stdio)
npm run dev	build + start
npm run typecheck	tsc --noEmit
npm test	ensure + build + unit + smoke
npm run test:unit	Helper unit tests
npm run test:smoke	Full MCP e2e vs fixture app
postinstall	Runs ensure-electron

Windows helpers: scripts/fix-electron.cmd · scripts/fix-electron.ps1

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🧪 Testing

npm test

Smoke path (v1.5):

initialize → tool/prompt/resource lists → start_app → evaluate → console/network/DOM → page_info / type_text / click / wait_for / press_key → save_screenshot (+ selector clip) → storage / cookies → start/stop_tracing → find_apps / attach_by_pid → screenshot → diagnose → attach → discover → stop

CI: .github/workflows/ci.yml (Ubuntu + Xvfb).

---

🗂️ Project layout

electron-mcp-server/
├── assets/logo.svg
├── examples/cursor-mcp.json
├── fixtures/minimal-electron-app/
├── scripts/ensure-electron.mjs · fix-electron.cmd · fix-electron.ps1
├── src/index.ts · process-manager.ts · events.ts · log.ts
├── test/mcp-smoke.mjs · unit-helpers.test.mjs
├── .github/workflows/ci.yml
└── README.md · LICENSE · package.json

---

🛡️ Security

• Can launch local binaries, evaluate JS in app contexts, read page content, cookies, and storage — treat as a powerful local debugger.
• Use ELECTRON_MCP_ALLOWED_ROOTS on shared machines.
• Don’t expose stdio over an open network without auth.
• Only attach / attach_by_pid to apps you trust (remote debugging is powerful).
• In-memory console/network buffers and exported traces may contain secrets from the app under test.

---

🧯 Troubleshooting

Symptom	Fix
Electron failed to install correctly	.\scripts\fix-electron.cmd / npm run ensure-electron
path.txt missing / dist=locales	Corrupt cache — repair script clears + uses tar
allowScripts warning	Expected on newer npm — run ensure/fix scripts
Hang + console title Select …	Windows QuickEdit — press Esc; disable QuickEdit
Empty console buffer	Wait for page activity; monitoring starts on start/attach; try set_console_live
wait_for / click fails	Selector not ready — wait first; screenshot to verify
Element screenshot hangs / times out	Headless/GPU quirks — server retries without fromSurface; ensure selector is visible
set_cookie fails on file://	Pass an http(s) url/domain
evaluate_main “No main/node target”	Restart with inspectMain: true or pass targetId
attach_by_pid can’t resolve port	App must be started with --remote-debugging-port; check find_apps
start_app path rejected	Outside ELECTRON_MCP_ALLOWED_ROOTS
node build/index.js “does nothing”	Waiting on MCP stdio — use Cursor config
Port in use	Change debugPort or discover_apps / find_apps
Linux headless	ELECTRON_MCP_NO_SANDBOX=1 + Xvfb
Tracing empty / fails	Call start_tracing before the slow path; only one active trace per session

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🤝 Contributing

1. Fork + branch
2. npm test
3. PR with tool/behavior notes
4. Keep stdout MCP-clean (log to stderr only)

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📄 License

ISC © Electron Debug MCP contributors

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Built for agents that need eyes — and hands — inside Electron.