Experimental

Conductor ships a set of commands that depend on React Native runtime internals (__REACT_DEVTOOLS_GLOBAL_HOOK__, fiber shape, UIManager / nativeFabricUIManager, renderer.rendererConfig). They work — they're modelled directly on the patterns used by tools like react-devtools — but RN reorganises these internals occasionally, so the scripts may need maintenance per RN major version.

If you hit a breakage, the failure mode is usually a clear error ("No React DevTools hook", "No fiber roots", "rendererConfig.getInspectorDataForViewAtPoint unavailable") and the underlying Metro / app is unaffected — you can fall back to native inspection.

All three groups below talk to Metro's Chrome DevTools Protocol endpoint (/json on port 8081 by default). Pass --port <n> to point at a different bundler, --target <n> to pick a specific debugger target when several are connected.

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RN debugger

Command	What it does
debug status	Show Metro target list, connection state, loaded scripts, enabled CDP domains.
debug evaluate <expr>	Runtime.evaluate in the app's JS context. Awaits promises. Reads Redux, calls app functions, inspects state.
debug component-tree	Walk the React fiber tree, batch-measure on-screen rects via UIManager.measureInWindow (Paper) or nativeFabricUIManager.measure (Fabric). Filters out wrapper noise.
debug inspect-element <x,y>	Use renderer.rendererConfig.getInspectorDataForViewAtPoint (React's own inspector) to find the component at a screen point. Walks UP via .return and resolves source via _debugStack / _debugSource.
debug log-registry	Summary of recent Metro console output — counts by level and clustering.
debug reload	Page.reload over CDP. Same as metro reload.

Caveats

• Requires Hermes (__REACT_DEVTOOLS_GLOBAL_HOOK__ is registered on Hermes startup).
• debug component-tree works on both Fabric and Paper, but the SKIP list of wrapper component names is hard-coded — new RN versions may surface new wrappers we don't filter.
• debug inspect-element requires getInspectorDataForViewAtPoint on the renderer; this exists on RN 0.70+. Older versions error out.
• Source frames come from _debugStack (RN ≥ 0.76) or _debugSource (@babel/plugin-transform-react-jsx-source). With neither, the frame is null.

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Network inspection

Command	What it does
network logs [--limit n]	Install a fetch/XHR shim into the running app (idempotent — only once per JS context) and read the captured entries. Each entry: { id, kind, method, url, status, durationMs, error, start }.
network request <url> [--method --body --header k=v]	Issue an HTTP request from the app's network context. Honours the app's cookies, headers, and TLS pinning.

Caveats

• Shim only sees fetch and XMLHttpRequest — apps that use native networking modules directly (e.g. okhttp on Android via a TurboModule) bypass it.
• A metro reload or app reload clears the shim — call network logs once to reinstall.
• The shim's ring buffer caps at ~200 entries; tune by re-installing if needed.

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Profiling

Command	What it does
profile frames report [--track <s>]	Android only. Parse dumpsys gfxinfo <pkg> framestats into jank counts, p50–p99 frame times, and a per-phase breakdown of where each frame's time went. Works on release builds and on real Fire TV hardware over adb. --save-baseline / --diff compare runs.
profile frames reset	Zero the counters, so the next report covers only what follows.
profile cpu --duration <s>	Record a CPU trace. iOS: xcrun xctrace record --template "Time Profiler". Android: adb shell simpleperf record. Writes to --out <path> or a tmp/ file.
profile cpu --report [--top n]	Android only. Also runs simpleperf report on-device and returns a ranked symbol table, so an agent gets something readable instead of a binary perf.data.
profile memory --track <s>	Poll memory at --interval <ms> (default 1000ms) for track seconds. On Android also reports heap growth over the window and ART GC pause counts / durations scraped from logcat.
profile js record --duration <s>	Run the Hermes sampling profiler over the Metro CDP connection. Returns a self/total time ranking by function with file:line, and writes the raw .cpuprofile.
profile js start / js stop	The same, bracketing a flow you drive yourself. A detached holder keeps the CDP session open in between.
profile react start	Install a React commit-profiler hook via __REACT_DEVTOOLS_GLOBAL_HOOK__.onCommitFiberRoot. --max-commits / --max-components size the buffers.
profile react stop [--top n]	Stop the profiler and rank components by self time. --json carries the per-commit timeline; --timeline adds per-commit component detail.
press-key <key> --measure	Time the response to an input. Reports focus→move latency (all platforms, with its own resolution as an error bar) and, on Android, the on-device input→frame latency from gfxinfo. --repeat n gives a distribution.

Caveats

• profile cpu requires xctrace (Xcode) or simpleperf (Android NDK) on PATH. --report uses the device's own /system/bin/simpleperf, which resolves against the libraries actually loaded there; a stripped app library still won't symbolize.
• profile react is Hermes-only and intercepts onCommitFiberRoot — interaction with other DevTools clients (the standalone React DevTools window, Flipper) is undefined; only run one profiler at a time.
• profile react needs a dev or profiling build. A release build strips React's timing instrumentation, and the command says so rather than reporting zeroes.
• profile react counts a component as having rendered in a commit only when React began work on it in that commit, tracked via an actualStartTime watermark. selfMs is additive across components; totalMs is subtree-inclusive and double-counts parents by design.
• profile memory is a polling shim over memory — for finer detail use the underlying conductor memory directly. ART only logs collections it considers noteworthy, so a window with no GC lines is a real signal rather than a parse failure.
• For which of these work against a Fire TV Stick, a Vega VVD, or an emulator — and how far to trust emulator numbers — see TV performance.

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When experimental graduates

Each command above moves to the main Command catalogue once it survives a full RN minor-version cycle without script changes. Until then, expect that an RN upgrade may briefly break one of these and a Conductor patch release will follow.