podium-mcp

A podium is where a maestro stands — one place to conduct the whole orchestra. This MCP server unifies eight capability sets behind a single stdio endpoint:

• Device & app management — iOS simulators (`simctl`), real iPhones (`devicectl`), and Android (`adb`) behind one platform-tagged device model.
• Native UI inspection & gestures — route through `idb`/`mobilecli` with a Maestro fallback (no per-gesture JVM spin-up).
• End-to-end flows & batch automation — declarative Maestro flows, ordered action batches, and an engineer→QA flow exporter.
• Trustworthy assertions — an *oracle ladder* (WebView-DOM › native a11y › Maestro) that returns falsifiable, evidenced verdicts and fails closed.
• WebView DOM + network — resolve `WKWebView` DOM to tap coordinates, evaluate JS, drive navigation, and capture in-page HTTP traffic as JSON/HAR.
• React Native debugging — Metro console logs, network requests, and in-app state over CDP, plus host/simulator crash reports.
• Real devices — Android emulator/device via `adb` (gestures + `uiautomator` hierarchy); real iOS via `devicectl` lifecycle + an opt-in WebDriverAgent backend.
• Canvas & game-engine automation, no vision — a *canvas/WebGL brain* drives Pixi/Konva/Fabric/Phaser/Three/Babylon UIs as addressable objects (validated live in WebKit). An experimental engine bridge drives Unity/GL via an AltTester-instrumented build (or a `window.__podiumEngine` WebGL bridge) — code-complete + mock-tested, not yet run against a live Unity build.

Rather than wiring several MCP servers into every client config, `podium-mcp` exposes everything behind one connection, with a shared `execFile` layer (no shell), consistent structured errors, automatic retry around Maestro's iOS-driver flakiness, and a single health-check tool to confirm what's available on the host.

Table of contents

• Why
• Benchmarks
• Requirements
• Install
• Usage
• Quick start
• The 51 tools
• The oracle ladder — trustworthy assertions
• Native-first gesture backend
• WebView & RN network introspection
• Documented limits
• Architecture
• Development & testing
• Roadmap & contributing
• Releasing
• Prompt playbook & references
• Design ideas
• Contributing · Security · License

Why

Driving a React Native app end-to-end usually means juggling several MCP servers —

one for device/app control, one for UI flows, one for Metro/debugger logs, another

for WebView inspection — each with its own config entry, quirks, and failure modes.

podium-mcp collapses that into one server with:

• a single `execFile`-based command runner (no shell — arguments are passed verbatim),
• consistent structured errors (a tool never crashes the server),
• automatic retry around Maestro's known iOS-driver flakiness,
• graceful degradation when a toolchain (e.g. `adb`) is absent,
• evidenced verdicts so an agent knows when a flow *actually* worked.

Benchmarks

Podium is built on two choices that make it fast and cheap: it drives UIs

as *structured data* — never screenshots — and routes gestures through a *native

backend* with no per-action JVM spin-up.

Token economics — no-vision is ~5× cheaper

A screenshot-driven agent sends an image to a vision model on every step.

Podium returns a compact structured element list instead. On an equivalent 8-step

mobile flow (1179×2556 screenshots vs ~20-element lists):

vision loop  ████████████████████████████████  16,557 tokens
Podium       ██████  3,117 tokens   (5.3× cheaper, −81%)

The gap compounds with every step — a 30-step session runs roughly **62k vs

12k input tokens. On top of per-step cost, the full 51-tool schema travels

with every request (~3,612 tokens, ~71/tool)**; Podium keeps tool descriptions

lean so the tool block never dominates the context window.

For canvas / WebGL UIs the advantage is structural, not just cheaper:

the Canvas Brain addresses objects by name and text, where a

screenshot-only agent must re-analyze pixels on every frame.

Speed — native-first gesture backend

Gestures route through `idb` / `mobilecli` instead of spinning up Maestro's JVM

per action (measured on a live iPhone 16 Pro simulator):

One connection, not six

All 51 tools — device & app control, UI automation, declarative Maestro flows,

evidenced assertions, WebView DOM + network capture, React Native / Metro

debugging, and no-vision canvas/WebGL automation (plus an experimental engine bridge for instrumented Unity/GL) — sit behind a **single

stdio endpoint**, replacing the usual stack of half a dozen separate MCP servers.

> Token figures are heuristic estimates (~4 chars/token; Anthropic's ~750 px/token

> image formula) — reproduce with `npm run token-bench`, or swap in the Anthropic

> `count_tokens` API for exact counts. Speed figures were measured on a live

> iPhone 16 Pro simulator (`npm run benchmark`).

Requirements

• macOS with Xcode command-line tools (`xcrun`, `simctl`)
• Node.js ≥ 22 (uses native `fetch` and `WebSocket`; `.npmrc` sets `engine-strict=true`)
• `mobilecli` — bundled automatically as an npm dependency; the default native gesture + WebView backend (no separate install)
• *(optional)* **`idb`** (`idb` + `idb_companion`) — preferred native gesture backend when both are present; auto-detected
• *(optional)* **Maestro** on `PATH` (or at `~/.maestro/bin`) — the `run_flow` engine and the gesture fallback path
• *(optional)* a running Metro bundler for the `metro_*` debugging tools
• *(optional)* Android SDK + `adb` — adb paths are detection-only and degrade gracefully when absent

> Platform scope (v0.3.0): podium automates iOS simulators, real iPhones (`devicectl` lifecycle + opt-in WebDriverAgent), and Android emulators/devices (`adb` gestures + `uiautomator` hierarchy). `device_list` tags each target with its platform and the backend is selected per target. When a toolchain (e.g. `adb`) is absent, those paths degrade to an informative result instead of failing.

Install

Claude Code plugin (recommended)

No manual config — one-time marketplace setup, then install:

/plugin marketplace add github:hoainho/podium-mcp
/plugin install podium-mcp@podium

The plugin auto-starts the MCP server (all 51 tools) and ships five skills:

npx (zero install)

{
  "mcpServers": {
    "podium": { "command": "npx", "args": ["-y", "podium-mcp"] }
  }
}

Manual (from source)

git clone git@github.com:hoainho/podium-mcp.git
cd podium-mcp
npm install
npm run build

Usage

Register the built server with any MCP client. Claude Code (`.mcp.json`):

{
  "mcpServers": {
    "podium": {
      "type": "stdio",
      "command": "node",
      "args": ["/absolute/path/to/podium-mcp/dist/index.js"]
    }
  }
}

Quick manual smoke test over raw stdio (lists the 51 registered tools):

printf '%s\n' \
  '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2024-11-05","capabilities":{},"clientInfo":{"name":"smoke","version":"0"}}}' \
  '{"jsonrpc":"2.0","method":"notifications/initialized"}' \
  '{"jsonrpc":"2.0","id":2,"method":"tools/list"}' | node dist/index.js

Always call `podium_health` first to confirm which toolchain is available on the host.

Quick start (order of use)

1. `podium_health` — confirm `xcrun` / `maestro` / native backend availability.

2. `device_list` — pick a booted simulator `udid`.

3. Read state — `app_list`, `app_state`, `screen_size`, `orientation_get`.

4. Drive the device — `app_launch`, then `tap_on` / `input_text` / `swipe` / `press_key`, plus `set_location` and `orientation_set`. Batch several with `run_steps`.

5. Author & verify — `inspect_screen` to discover elements, `run_flow` for declarative checks, then `assert_visible` / `validate_flow` for an evidenced verdict.

6. Inspect WebViews — `webview_inspect` → tap coordinates, `webview_eval`, `webview_navigate`, `webview_network`.

7. Capture & debug — `screenshot` / `record_start`→`record_stop`; `metro_logs` / `metro_network` / `metro_state`; `crash_list` / `crash_get`.

The 51 tools

> Every tool returns structured JSON and never throws — failures come back as MCP tool errors. See `docs/tool-catalog.md` for the authoritative per-parameter reference.

>

> Platform support (v0.3.0): the gesture / inspect / lifecycle tools below run on iOS simulators, real iPhones (`devicectl` + opt-in WebDriverAgent via `PODIUM_WDA_URL`), and Android (emulator/device via `adb`; hierarchy from `uiautomator`). `device_list` tags each device with its platform and the backend is selected per target.

Game engine — Unity / GL via AltTester, no vision · experimental (4)

> Status: experimental. The wire shapes are unit-tested against mocks; the AltTester path has not yet been validated against a live Unity build (`engine-smoke` skips until an instrumented build is provided), and Unity-WebGL needs the app to expose `window.__podiumEngine`. Engine tools require an AltTester-instrumented build (dev/staging) or that WebGL bridge; on a non-instrumented build they fail closed with an actionable error — never a vision fallback. For canvas/WebGL apps using a JS framework, the canvas brain below is the validated path.

Canvas brain — Pixi/Konva/Fabric/Phaser/Three/Babylon, no vision (3)

> Validated live: all six frameworks pass a Playwright-WebKit (≈ WKWebView) suite at DPR 1 + 3 (`npm run test:canvas`, 19 tests). Canvas tools require an inspectable WKWebView hosting a supported framework with its root reachable (commonly on `window`, or Pixi's `__PIXI_APP__`). No framework / no inspectable WebView → fails closed with an actionable error — never a vision fallback.

Diagnostics (1)

Health & toolchain (1)

Device & simulator (6)

Apps (6)

Capture (3)

UI inspection & gestures (8)

Flows & batch automation (4)

Assertions & verdicts — the oracle ladder (5)

WebView DOM & network (4)

React Native debugging — Metro CDP (4)

Crash diagnostics (2)

The oracle ladder — trustworthy assertions

"It works" is operationalized as a falsifiable, evidenced verdict — never "looks ok". Assertions and `validate_flow` resolve visibility through a three-rung ladder, using the strongest available signal:

1. WebView DOM — when an inspectable `WKWebView` is present, query the real DOM.

2. Native accessibility — the native AX element set (via `idb`/`mobilecli`).

3. Maestro — `assertVisible`/`assertNotVisible` as the fallback.

`assert_not_visible` fails closed: if absence can't be positively verified (e.g. a WebView is unreadable), it reports failure rather than a false pass. Every verdict names the oracle that produced it, so an agent can weight its confidence.

Native-first gesture backend

Imperative gestures (`tap_on`, `input_text`, `swipe`, `press_key`, `orientation_set`, `run_steps`) and `inspect_screen` route through the fastest available backend, probed once and cached (with a short negative-cache TTL so a backend that starts after launch is picked up):

1. `idb` — when both `idb` and `idb_companion` are installed (native, fastest).

2. `mobilecli` — the bundled npm dependency (prebuilt Go binary). Default; no install.

3. Maestro fallback — when no native backend resolves, or for actions it can't express (double/long-press, `UPSIDE_DOWN`). The gesture generates a minimal flow with `launchApp: { stopApp: false }`, foregrounding the app without restarting so state is preserved.

Each result reports the `backend` it used. Set `PODIUM_DISABLE_NATIVE=1` to force Maestro. Eliminating the per-gesture JVM spin-up cut `tap_on` ~14.7 s → ~0.6 s and `inspect_screen` ~8.9 s → ~0.9 s on an iPhone 16 Pro simulator. Run `npm run benchmark` for a full pass/fail sweep.

Maestro flakiness retry: when the fallback runs, its iOS driver intermittently fails with `Failed to connect to 127.0.0.1:`. Flows retry up to 2× with 2 s / 5 s backoff and report the `retries` count; a persistent failure returns the raw output with remediation hints.

WebView & RN network introspection

Two distinct network layers, two tools:

• `metro_network` captures requests on the RN/Hermes target via the CDP Network domain — the right tool for a native RN app's own `fetch`.
• `webview_network` captures traffic inside a `WKWebView`: it injects a `fetch`/`XHR` recorder (rich — method/status/headers/body for calls *after* capture starts) and reads the browser's Performance Resource Timing buffer (`includeResources`, default on) — every request since navigation, including pre-capture ones (URL/timing/size). The merge yields a near-complete request list, exported as redacted JSON or HAR 1.2.

For an RN shell that hosts its UI in a WebView, the app's API calls run in the web layer — so `metro_network` sees nothing and `webview_network` is the tool to reach for. WebView tools require `WKWebView.isInspectable = true` (default in debug/staging builds; off in production); when none is found they return an actionable error.

Documented limits (by design, not bugs)

• Canvas/WebGL needs a cooperating JS framework — the canvas brain automates Pixi/Konva/Fabric/Phaser/Three/Babylon UIs by selector when the app exposes its scene-graph root (validated live). A raw/custom WebGL canvas, an opaque/production build, or Unity without an AltTester / `window.__podiumEngine` bridge is not selector-addressable — fall back to `tap_with_fallback` with screenshot-derived coordinates, or instrument the build.
• WebView tools are dev/QA only — production App Store builds typically set `isInspectable = false`; tools return an actionable error and fall back to coordinate taps.
• WebView content-process memory is unreadable from the app sandbox (platform limit) — use indirect signals (memory warnings, process terminations).
• Maestro `text:` matcher is full-string regex (IGNORE_CASE) — partial strings don't match; copy hierarchy `text` verbatim or anchor with `.*`.
• Android requires `adb` on `PATH` — gestures / inspect / screenshot work once `adb` is present; when it's absent every Android path degrades to a structured "adb not found" result.
• `orientation_get` is a screenshot-aspect heuristic when no native backend is present — iOS simulators expose no direct orientation query.
• `record_start`/`record_stop` keep state in-process — serialize `start` → … → `stop` on one connection; one active recording per udid (a watchdog finalizes one that's never stopped).

Architecture

src/
  index.ts          # MCP server entry — registers every tool group, warms caches
  lib/
    exec.ts         # execFile-based runner (NO shell) + timeout/timedOut flag
    result.ts       # shared ok/error MCP content helpers
    simctl.ts       # xcrun simctl wrappers + device-list TTL cache
    native.ts       # gesture/inspect backend: idb → mobilecli → null (re-probe TTL)
    idb.ts          # idb gesture/inspect adapter
    gesture.ts      # unified native→Maestro executors (shared by screen + steps)
    oracle.ts       # the oracle ladder: WebView-DOM › a11y › Maestro
    maestro.ts      # Maestro engine: flow runner, idb retry, hierarchy
    export-maestro.ts # run_steps → reusable Maestro flow
    har.ts          # HAR 1.2 export for webview_network
    webview.ts      # mobilecli CDP — WebView list/inspect/eval/navigate/network
    metro.ts        # Metro CDP — app discovery, logs, network, state
    crash.ts        # DiagnosticReports crash listing/reading
    recording.ts    # detached screen recording lifecycle + watchdog (platform-aware)
    device-target.ts # DeviceTarget model + PlatformDriver registry (v0.3.0)
    drivers/        # per-platform lifecycle: ios-sim, android, ios-real
    adb.ts          # Android adb driver (list/install/launch/screenshot/wm size)
    adb-backend.ts  # adb gesture/inspect (input + uiautomator → AX elements)
    iosreal.ts      # real iOS via devicectl (list/install/launch) + capture
    wda.ts          # opt-in WebDriverAgent backend (/source + tap/swipe/keys)
    engine.ts       # no-vision engine client (AltTester + WebGL-in-WebView)
    engine-transport.ts # WebSocket transport for the AltTester bridge
    canvas-types.ts # Canvas Brain shared contract (CanvasObject, selectors)
    canvas-adapters.ts  # in-page bridge: detect + walk Pixi/Konva/Fabric/Phaser/Three/Babylon
    canvas-resolver.ts  # semantic "close brain": intent → ranked, evidenced target
    canvas-a11y.ts  # Flutter/ARIA fallback reader → CanvasObject (scaffolding, not wired — #9)
    canvas-vision.ts # opt-in vision fallback scaffolding (not wired — #9)
    token-report.ts # token estimators + no-vision vs vision-loop comparison
  tools/            # one file per group:
                    #   health, device, screen, steps, flow, assert, validate,
                    #   webview, debug, engine, canvas, token
assets/             # bundled offline Maestro cheat sheet + demo.gif
scripts/            # benchmark.ts, compare-mcps.ts, token-bench.mjs
e2e/                # smoke suites (smoke / full-smoke / webview-network-live / android-smoke / engine-smoke)
test/canvas-e2e/    # live Playwright-WebKit canvas bridge suite (6 frameworks)
docs/               # tool catalog, e2e transcript, roadmap, token-economics

Development & testing

npm run build       # tsc
npm run typecheck   # tsc --noEmit
npm test            # vitest run — 359 unit/integration tests (exec/network mocked, no sim needed)
npm run test:canvas # live canvas bridge suite in Playwright WebKit — 19 tests (run `npx playwright install webkit` first)
npm run benchmark   # spawn a fresh server over stdio and sweep the tool suite
node e2e/smoke.e2e.mjs        # real E2E against a booted simulator (macOS + Xcode)
node e2e/full-smoke.e2e.mjs   # drives the iOS-sim tool handlers (happy + structured-error paths)
node e2e/android-smoke.e2e.mjs # Android emulator/device smoke (story A3)
node e2e/engine-smoke.e2e.mjs  # AltTester engine smoke; skips without an instrumented build (story C4)

359 unit/integration tests across 31 files, plus 19 live canvas-bridge tests (378 total), all passing — including the v0.3.0 device-target registry, the Android `adb` driver + `uiautomator` parser, the AltTester engine client + WebGL bridge, the `devicectl`/WDA real-iOS parsers, plus the v0.2.0 oracle ladder, recording watchdog, gesture-parity, HAR export, WebView, and Metro paths.

Standards: TypeScript strict, no `as any` / `@ts-ignore`, no shell execution (all commands via `lib/exec.ts`), tools return structured errors instead of throwing. See CONTRIBUTING.md for the "add a new tool" checklist.

E2E on CI: the `E2E (simulator)` workflow boots a real iOS simulator on a macOS runner and runs the smoke suites nightly + on demand (not a PR gate — simulator runs are slow). `full-smoke.e2e.mjs` asserts the happy path where a target exists and the real structured-error path where a dependency is absent (a debug `isInspectable` app for WebView; a connected RN app for `metro_*`).

Roadmap & contributing

podium-mcp is production-ready for iOS/Android UI automation and no-vision canvas/WebGL (Pixi/Konva/Fabric/Phaser/Three/Babylon — validated live). The frontier, where a contributor can make a real dent, lives in open issues:

High-impact — `help wanted`

• #1 — validate the AltTester/Unity engine path against a live instrumented Unity build (the biggest gap to real Unity automation).
• #2 — real-device WKWebView e2e for the canvas brain (today validated in Playwright WebKit).
• #3 — Unity-WebGL adapter: auto-detect + a drop-in `window.__podiumEngine` bridge.

Good first issues — `good first issue`

• #4 — more canvas adapters (PlayCanvas, Cocos Creator, p5.js).
• #5 — expose `canvas_hittest` / `canvas_object_rect` tools.
• #7 — exact token counts via the Anthropic `count_tokens` API.
• #6 — address Konva Group/Container targets.

Adding a tool follows one checklist in CONTRIBUTING.md: TypeScript strict, no shell, structured-errors-never-throw, a vitest test, and a row in the tool catalog. PRs welcome.

Releasing

`server.json` is the official MCP Registry manifest. Pushing a `v*` tag runs

`Publish to npm` then

`Publish to MCP Registry` (GitHub OIDC for the

`io.github.hoainho/*` namespace — no long-lived token). Both workflows run `typecheck → build → test`

as a gate first; the registry publish only succeeds once the matching npm version is live, and

versions are immutable.

Prompt playbook & references

• **`prompts/`** — copy-paste prompts for e2e flows, test cases, feature verification, bug fixing, and device control. Each names the podium tools it drives and was validated on a real simulator. Start with `prompts/README.md`.
• **`docs/tool-catalog.md`** — authoritative tool-by-tool reference.
• **`docs/e2e-demo.md`** — a real transcript against a booted iPhone 16 Pro simulator running a production RN app.

Design ideas

• One podium, one connection. A single server fronts every mobile capability so an agent configures one endpoint and discovers all 51 tools at once.
• Safe by construction. Every external command runs through an `execFile` layer with an explicit argument array — never a shell string.
• Never crash the conductor. Tools return structured results and errors instead of throwing; one bad call can't take the server down.
• Degrade, don't fail. A missing toolchain (e.g. Android's `adb`) yields an informative result rather than a hard error.
• Prove it, don't guess. Assertions return evidenced verdicts via the oracle ladder and fail closed when they can't verify.

Contributing

Contributions welcome — see CONTRIBUTING.md and the

Code of Conduct. Use the issue templates for bugs and feature requests.

Security

Please report vulnerabilities privately per SECURITY.md — do not open a public issue.

SECURITY.md also documents the `webview_eval` / `run_flow` trust boundary and the PII-in-transcript caveat.

License

MIT © 2026 hoainho