Rn Devtools Hub README
The full upstream README, mirrored here for reference. Install config, tool schemas, adoption signals, and an original overview live on the Rn Devtools Hub listing page.
rn-devtools-hub
The agent runtime for React Native. Your agent sees the app the way React sees it, knows which file produced each element, acts without coordinates, and proves that it works. Zero dependencies, no telemetry or usage counting, with a local hub and SDK.
Documentation · Quick start · Integration · Contributing
Use it from an agent
Both plugins install the MCP server plus a skill that teaches the agent to chain its tools: check the project context before debugging anything that looks impossible, prove results with assertions instead of screenshots, wait on events instead of sleeping, and read an element's source instead of grepping the repository.
Claude Code
Codex
Then start the hub at the root of your app, which is what the agent talks to:
Registering the server by hand works too. Claude Code:
Codex, in ~/.codex/config.toml:
Cursor has no marketplace, so it is two files in your own project.
Declare the server in .cursor/mcp.json:
And copy the rule, which is the Cursor equivalent of the skill:
It ships with alwaysApply: false, so Cursor pulls it in when the task
matches instead of paying for it on every request.
For any other agent, the skill on its own comes from the skills.sh registry:
It writes .agents/skills/rn-devtools-hub and links it into whichever
agents it detects, from Gemini CLI and Copilot to Windsurf and Zed. This
installs the skill only, so register the server as above and start the hub
to give the agent something to talk to.
Any client that speaks only stdio uses npx rn-devtools-hub mcp, which
bridges to the hub and starts it on demand.
When a testing or debugging task starts, the agent is instructed to announce
the project and its clickable dashboard URL, then continue automatically.
The hub supplies the actual bound port and current token, including when a
second project uses a fallback port. The link is also available in the
dashboard field of list_devices, get_project_context and session_start.
Screenshots
Overview: request counts, error rate, JS thread lag, connection and device at a glance
Network: colored methods, slow requests highlighted, foldable JSON, copy as cURL, secrets redacted before they leave the device
Mirror: the live device screen over adb, click to tap, drag to swipe, wheel to scroll, plus Back/Home/Recents/Dev menu
Tools: what the agent did and what the app did back, calls per tool split into answered / empty / failed, failures grouped by message, empty answers with the reason the tool gave, and the context each answer bills the agent
Why
The SDK lives inside the JavaScript runtime of your app.
The SDK executes directly alongside your application code. It reads React's tree, invokes handlers, instruments requests and reaches registered stores through APIs installed inside the app. The hub receives these capabilities over its own local connection, without requiring a debugger protocol session. Other tools can access runtime internals through protocols such as CDP; the hub's foundation is an explicit in-app SDK and its event contracts.
That position is what the whole product is built on. Everything else follows from it:
| The agent can | Because it is inside the runtime |
|---|---|
| Find an element by role and accessible name, then act on it | Actions go through the app's own props, not through pixels |
| Get the file and line that produced an element | The location lives in React's dev bookkeeping |
| Prove a step without a screenshot | A screenshot cannot show a request that failed silently |
| Tell a stale native build from a code problem | Only the runtime knows what the binary actually is |
| Freeze the clock and the network | Date and fetch are in the runtime |
| Put the app in an exact state without walking ten screens | Stores are reachable directly |
| Explain a visual regression, not just score it | The changed region maps back to the component that owns it |
A pure JavaScript SDK in the app (inert in production), a local hub in a single process, a dashboard in the browser. Zero dependencies anywhere, including the hub. The hub has no telemetry. MCP results are delivered to your agent and may be sent to its model provider. Configured store plugins contact their declared vendor endpoints.
Features
| Panel | What you see |
|---|---|
| Overview | KPI tiles, JS thread lag, HTTP statuses, duration distribution |
| Crashes | Fatal errors, JS errors, unhandled promise rejections, stacks |
| Network | Request/response inspector (colored methods, durations, sizes), copy as cURL, secrets redacted |
| Uploads | Live upload queue (if your app emits the events, see the protocol) |
| Cache | React Query snapshot: keys, statuses, freshness, data |
| Storage | AsyncStorage keys, sizes, values, live write timestamps |
| Screens | Navigation journey, time spent per screen |
| Logs | console.log/info/warn/error, colorized JSON, filters |
| SQLite | Read-only SQL console (SELECT/PRAGMA) on your app's database |
| Endpoints | Map of declared endpoints, calls, latencies |
| Actions | Buttons driving the app: reload, clear caches, your custom actions |
| Tests | Human-readable .hubflow scenarios, live replay progress, failure diagnosis, approved visual evidence and safe target repair candidates |
| Tools | What the agents do with this hub: calls per tool, failures with their message, empty answers and why, context bytes returned (pixels counted separately, because a session spending most of its context on screenshots is a session verifying the expensive way), selectors used, and the loop replayed against the app's own events |
| Plugins | The services around the app: App Store Connect and Google Play, what each one is configured with, whether it may change a release, and every host it will contact |
| Design | Icon, splash, fonts, sounds, identity (read from app.json and the assets) |
| Mirror | Live app screen (needs react-native-view-shot in the app), full Android via adb (tap, swipe, keyboard, Wi-Fi), iOS simulator via xcrun |
The Overview panel opens with the project context: what the project declares, what the app actually runs, and whatever the two disagree on. A stale native build is the most common way to lose an afternoon here, and it is named before you start reading code.
Plus: multi-device with merged sessions, bug report export in Markdown (ready for a GitHub issue), real-time capability badges, and a local MCP server to drive everything from Claude, Cursor or any MCP client.
See Hubflow scenarios to record an exploration, save it as a runtime regression test, replay it in CI and inspect its selected success or failure screenshots in the dashboard.
What an agent gets
| Tool | What it answers |
|---|---|
get_project_context | What the project declares, what it actually runs, and the contradictions. Call it first when anything behaves impossibly |
get_ui_tree, query_ui | The visible components, each carrying the source file and line that produced it |
ui_act | Tap, type, submit, scroll, by element and never by pixel |
assert | Proves a step: element kinds retry, event kinds catch a request that failed silently, a console error, an unhandled rejection |
freeze_time, mock_network | Deterministic at the JS level, so a scenario runs the same twice |
get_state, set_state | Put the app in an exact state without walking ten screens |
render_component | Mount a component inside the running app, under its real providers |
snapshot_baseline, compare_snapshot | A visual diff that names the component owning the changed region |
export_session, export_flow | One correlated timeline, and actions paired with the consequences they caused |
save_flow, list_flows, get_flow, run_flow, propose_flow_repair | Persist a runtime scenario, replay it with assertions and screenshots, and create a reviewable repair candidate when a strongly identified target moves |
audit_accessibility | What React renders but the accessibility tree does not expose |
list_plugins, asc_*, gplay_* | The release around the app: has the build finished processing, where is the version in review, what is production serving, what do the store reviews say. And driving it: distribute to TestFlight, submit for review, promote a track, widen or halt a staged rollout |
capture_store_screenshots | Regenerate the App Store and Play screenshots from the running app: devices, locales and screens from a manifest, each reached with the app's own dev actions, captured at native resolution and uploaded. The pixels never enter the agent's context |
Source locations survive React 19, where the location lives in owner stacks pointing into the bundle: the hub symbolicates them against Metro before the agent sees them.
For AI agents, the hub also exposes runtime UI automation over MCP:
get_ui_tree (semantic tree of the visible components, read from the React
runtime, including native views without accessibility like maps), query_ui
(find elements by role and accessible name, testID, placeholder, text or
label, scoped with within, with measured rects), ui_act (tap, type exact
text, submit, scroll, all by element, never by pixels, and it reads the
field back to say whether the text landed), typed dev actions
(list_actions/run_action: navigate, seed, login without touching the
UI), and a correlated event flow (wait_for_event, get_events_since) that
replaces sleeps with real signals like screen.ready. Works in Expo Go,
development builds and bare React Native, and in CI without any simulator:
enable it with devtools.attachUiAutomation().
The hub covers the native layer too, as a superset of what idb/simctl
scripting gives an agent: session_start boots a dev build on the right
Metro server with zero dialogs (permissions pre-granted, dev-menu
onboarding skipped), plus set_permission, launch_app, open_url,
screenshot_native, set_location, send_push, set_appearance,
set_animations, set_overlay (the expo-dev-menu bubble covers native
controls no UI tree can show) and the last-resort tap_native and
swipe_native, on iOS simulators and Android devices, with every capability
probed and degrading cleanly.
Everything above stops at the machine. The half of a release that does not is behind a plugin: App Store Connect and Google Play ship with the hub and stay inert until you give them credentials. They read a release and they drive one, so the agent that decides to widen a rollout is the agent that already has the crash evidence for it. Installing the hub's plugin installs the release skill with it, so there is nothing else to add.
A configured plugin prints the hosts it will contact at startup, an
unconfigured one exposes no tool at all rather than costing an agent context
it cannot use, and RN_DEVTOOLS_PLUGIN_WRITES=off removes every tool that
could change anything. See docs/plugins.md.
Quick start
Prerequisites: Node 20+. Bun is used when present, and is not required. Optional capabilities (adb mirror, iOS simulator, Wi-Fi) have their own prerequisites: see the integration guide.
init inspects your project and generates only the code it can actually
run: axios interception if you use axios, the Storage panel if you have
AsyncStorage, device info if you have expo-device, and so on. It never
overwrites an existing glue file (use --force), and --dry-run shows
what it would change.
That's it: logs, crashes and performance already flow in. Every additional integration (network, cache, storage, SQLite, mirror...) is a recipe of a few lines: see the integration guide.
Integration guide
The SDK is agnostic: it exposes generic primitives that you wire to YOUR libraries. All the recipes are in docs/integration.md, notably:
devtools.attachAxios(instance, "api"): any axios instancedevtools.wrapFetch(fetch, "uploads"): any fetch-based clientdevtools.emit(type, payload): feed any paneldevtools.onCommand(name, handler): respond to the dashboard (e.g. SQLite)devtools.registerAction({name, label, danger, requiresNative}, handler)devtools.attachUiAutomation(): UI perception and actions for AI agentsdevtools.markScreenReady("Login"): "screen ready" signal agents wait on- The complete events and commands protocol: docs/protocol.md. It is the contract: any tool (or any LLM) can integrate a panel by implementing it.
Host project dependencies
The SDK imposes NOTHING. Depending on the features you want, add to YOUR project:
| Feature | Install in your project | Type |
|---|---|---|
| The package itself | rn-devtools-hub | devDependencies |
| App mirror (screen stream) | react-native-view-shot | dependencies (included in Expo Go) |
| Storage panel | @react-native-async-storage/async-storage | already present in most apps |
| SQLite console | expo-sqlite (or your driver + a sqlite.query handler) | depends on your app |
| Enriched device info | expo-device, expo-application, expo-network | dependencies |
| Full Android mirror | adb on the dev machine (not in the app) | system tool |
| iOS simulator mirror | Xcode command line tools (dev machine) | system tool |
Security
- The SDK is inert outside
__DEV__(double guard: yours and the SDK's) - The dashboard requires a token (printed at startup,
RN_DEVTOOLS_TOKENto pin it) - Sensitive headers (Authorization, cookies, x-api-key) are redacted before leaving the device
- The SQLite console only accepts SELECT and PRAGMA
- The MCP server only listens on localhost, with Origin verification
- Design panel assets are confined to the project root, with whitelisted extensions
- Plugins are the only outbound path, they are inert without credentials, each one declares the hosts it contacts, and no credential is ever returned by a tool or written to a log
- Every plugin tool that changes something is declared as such, is
annotated so MCP clients confirm it, and can be removed entirely with
RN_DEVTOOLS_PLUGIN_WRITES=off RN_DEVTOOLS_SCREENSHOTS=off(or a number) removes or budgets pixel captures, for teams who do not want an agent verifying with screenshots
Contributing
Contributions are welcome. The full guide is in CONTRIBUTING.md. In short:
- Commits follow Conventional Commits
(
feat:,fix:,docs:...): the changelog and versions derive from them automatically (release-it), and commitlint checks them at commit time - The pre-commit hooks run typecheck + tests
- Release:
npm run release(maintainers)
For AI agents: read AGENTS.md and llms.txt.