/eas-simulator

Controllers: agent-device, Appium, and argent

eas-cli has no device verbs — it manages the session. Automation commands come from the interface selected by simulator:start --type:

• agent-device (Callstack, MIT) — used throughout this skill; runs on demand via npx agent-device@latest, nothing installed globally.
• appium — exposes APPIUM_URL and APPIUM_CAPS for an Appium client.
• argent (Software Mansion) — a capable alternative controller; check its license for your use.
• web-preview-only — browser preview with no programmatic control.

All four types include a web preview. Before setting --max-idle-time-minutes, follow Session lifetime; activity does not reset the timer for every interface.

Appium

Start with --type appium, then run the user's Appium client through simulator:exec; the wrapper loads APPIUM_URL and JSON-encoded APPIUM_CAPS from .env.eas-simulator:

npx --yes eas-cli@latest simulator:start --platform ios --type appium --non-interactive \
  --name "Appium checkout run"
npx --yes eas-cli@latest simulator:exec <appium-client> [args...]

Use the maximum duration as the lifetime bound; Appium commands do not reset the idle timer.

agent-device verbs (run via npx --yes eas-cli@latest simulator:exec npx agent-device@latest <verb>)

agent-device is a thin client talking to a daemon (the daemon runs on the VM in a session). npx --yes eas-cli@latest simulator:exec sets AGENT_DEVICE_DAEMON_BASE_URL + AGENT_DEVICE_DAEMON_AUTH_TOKEN from .env.eas-simulator, which switches the client into remote mode. Selectors and @e-refs come from the latest snapshot.

The CLI help is written for agents and is the source of truth — run these for the full verb set and agentic loop guidance:

npx --yes eas-cli@latest simulator:exec npx agent-device@latest --help
npx --yes eas-cli@latest simulator:exec npx agent-device@latest help workflow

EAS-specific notes:

• press, not tap. The tap verb is press — tap is not a verb.
• snapshot -i is slow on iOS — tens of seconds is normal; wait for it.
• install uploads a local binary to the daemon; install-from-source has the VM download from a URL (use for EAS artifacts — avoids a large upload).
• Exercised against a live session: apps, install, install-from-source, open, snapshot -i, press, fill, screenshot, scroll, gesture (needs a preset, e.g. gesture swipe left), logs, record (start/stop <path>), network, perf. metro (prepare/reload) is the Mode C dev-client bridge. Pass --platform ios; run <verb> with no args to see its required subcommand/args.

Recording download recovery

If downloading a recording through agent-device or argent fails, fetch the recording from EAS session artifacts. A controller download failure does not mean the recording was lost. Keep the original EAS session id and query its artifacts:

npx --yes eas-cli@latest simulator:get --id <session-id> --json
# Select the recording in artifacts[] by filename/name and metadata; use its downloadUrl:
curl --fail --location --max-time 600 --output ./capture.mp4 '<downloadUrl>'

Use the URL returned by EAS, not a path on the simulator or a controller artifact id. If the recording has not appeared yet, poll the same session with a bounded wait for upload completion. Already-uploaded artifacts can be retrieved after the session stops using its explicit id. If a download URL expires, query the session again for a fresh one. Give the download command more than 10 minutes in the outer runner, increase --max-time for larger files, and verify the downloaded video before reporting success.

Source: EAS CLI simulator:get exposes artifacts[].{id,name,filename,metadata,downloadUrl}.

argent (alternative)

npx --yes eas-cli@latest simulator:start --type argent provisions an argent remote session. The connection config it returns is different (ARGENT_TOOLS_URL / ARGENT_AUTH_TOKEN).

Invoking argent — run its tools directly. Drive argent with npx --yes eas-cli@latest simulator:exec argent run <tool> --udid <udid> …. simulator:exec is strict = false and hands the command its args verbatim (it spawnAsync(command, args) with the session env loaded), so argent's --flags pass straight through — no sh -c wrapper and no --args JSON blob needed. (You can also drive argent via its MCP server, which passes structured params.) argent's gesture tools take normalized 0.0–1.0 coordinates, not pixels — check its help for the exact input shape.

Installing apps in an argent session. --type argent provisions only an argent daemon on the VM — there is no agent-device daemon, so agent-device install verbs don't apply. Install a local build with argent's own reinstall-app (tar-upload):

argent run reinstall-app --udid <udid> --bundleId <bundle-id> --appPath ./MyApp.app

Whenever the tools client is routed to a remote tool-server, it tars the local bundle and streams it up automatically — no extra flag. "Remote" covers both argent link and the env-var MCP config (ARGENT_TOOLS_URL), so this works in sandboxed shells too. It's a registry tool, so the MCP server exposes it identically — same call by CLI or MCP. Works for iOS .app (a directory), Android .apk, and Vega .vpkg; the client prints an upload line on stderr.

Needs argent ≥ 0.16.0 (the release that adds tar-upload) — verify with argent --version. On older versions reinstall-app resolves --appPath on the VM only, so a local path fails; drive an app already on the sim instead.

Mode C (dev client) on argent. Easiest is the native launch (eas-cli ≥ 22.4.0): simulator:start --type argent --build-id <id> --launch-arg … --open-url "<scheme>://expo-development-client/?url=<metro-url>" installs, launches, and connects the dev client with the launch-args applied and the "Open in?" dialog auto-handled — same as agent-device Method 1 (see run-your-app.md). No manual open-url or coordinate tap. argent needs no open --foreground attach either; argent run screenshot works against the running app, but pass an explicit --udid from list-devices (the Booted one — there's no default), and it saves to a LOCAL temp path.

To drive the connect yourself on a bare argent session (no launch flags), argent has open-url, which opens a scheme / deep link directly, so you can point a dev client at Metro without tapping through the launcher. Use the dev-client custom scheme (not https://, which can fall through to Safari):

# load the dev client from Metro via its deep link
npx --yes eas-cli@latest simulator:exec argent run open-url --udid <udid> --url "<scheme>://expo-development-client/?url=<metro-url>"
# open-url raises the "Open in '<app>'?" system dialog — argent has NO alert-accept, so screenshot to
# locate "Open", then coordinate-tap it (its describe may not see the dialog — see "System dialogs" below)
npx --yes eas-cli@latest simulator:exec argent run screenshot --udid <udid>
npx --yes eas-cli@latest simulator:exec argent run gesture-tap --udid <udid> --x <0..1> --y <0..1>
# then attach to Metro's debugger / reload the bundle
npx --yes eas-cli@latest simulator:exec argent run debugger-connect --udid <udid>

Where argent is weaker than agent-device Mode C — so it's capable, not as fast:

• No launch-args. launch-app takes only --bundleId; argent can't pre-seed -EXDevMenuIsOnboardingFinished / -EXDevMenuShowsAtLaunch the way agent-device's open --launch-args does. If the onboarding popup or dev menu blocks the screen, tap through it by normalized 0.0–1.0 coordinates (gesture-tap, positions from describe / native-describe-screen) — there's no element/ref tap.
• No Metro bind on launch. No --metro-host / --bundle-url seed; point the client at Metro with the open-url deep link above, then debugger-connect / debugger-reload-metro.
• Whole-string text entry: use keyboard --text "<string>" — it types the entire string in one call. Never type character by character.

System dialogs on argent (e.g. the first-time deep-link "Open in '<app>'?"). argent's UI queries (describe / await-ui-element) may not see system dialogs / native modals — a screenshot shows the dialog, but element lookups time out. When that happens, argent surfaces a hint with the fix (today that's a boot-device --force to switch its AX backend); follow the hint, then locate and tap "Open". There's no single press-with-timeout — you wait for the element, then tap it. Use argent's own command help for the exact tools and flags.

Recording video on argent (screen-recording-start/stop). The gotcha to know: argent trims static stretches by default, which drops the very frames you're measuring — turn that off when you care about cadence or timing (see argent's help for the flag). Recordings also carry a burned-in "Argent" watermark that can't be disabled on a hosted session — fine for diagnosis, mind it before sharing publicly. The stop call returns a video already downloaded locally; extract frames with ffmpeg (may need installing) to inspect motion frame by frame. The capture samples at ~30fps, so it shows visible jank but can't prove or disprove sub-frame hitches on 60/120Hz content.

Screenshot resolution and token cost. Screenshots cost context tokens once the agent reads them, so resolution is a real tradeoff. argent's screenshot has two independent levers. scale sets the image resolution and defaults low (too coarse to judge layout), so pass a larger scale when you need to read the UI. includeImageInContext:false keeps an image out of the agent's context entirely (zero token cost) — use that for a baseline you'll only diff later, and keep that one at full resolution so the pixel diff stays accurate. So: scale down images you actually read; drop unread ones with includeImageInContext, don't just shrink them. Exact flags and the current default: argent's help.

agent-device screenshots default to full resolution — a crisp PNG you read from disk, token-heavier for its size, so match the capture to the question. From v0.20.6 it gains the same lever argent has and drops the old one: screenshot --scale <0.01–1> proportionally resizes both dimensions (1 = full resolution), with a token-conscious default via AGENT_DEVICE_SCREENSHOT_SCALE (or screenshotScale in config) that an explicit --scale overrides — keep it unset or 1 for pixel-diff baselines; the former --max-size is removed (older calls refused with migration guidance). Verify the version with agent-device --version. One caveat for remote sessions: the resize runs on the daemon, so a newer client against an older EAS session daemon can have --scale silently ignored and get full-res back.

Connecting via MCP (Cursor, Claude Code, Codex, and others). Install the CLI globally first — the package is @swmansion/argent, not argent:

npm install -g @swmansion/argent

Then run argent init --yes to register the Argent MCP server. Link the session credentials with argent link — the recommended path:

argent link '<ARGENT_TOOLS_URL>' --token '<ARGENT_AUTH_TOKEN>' --yes

Reload the agent after linking so its argent mcp process picks up the remote session.

Sandboxed shells (Claude Code, some CI environments) can't write to ~/.argent/ so argent link won't work there. Use env vars in the MCP config file instead — this is argent's highest-precedence resolution and overrides any link:

{
  "mcpServers": {
    "argent": {
      "command": "argent",
      "args": ["mcp"],
      "env": {
        "ARGENT_TOOLS_URL": "<ARGENT_TOOLS_URL from simulator:start>",
        "ARGENT_AUTH_TOKEN": "<ARGENT_AUTH_TOKEN from simulator:start>"
      }
    }
  }
}

MCP config file location: .cursor/mcp.json (Cursor), .claude/mcp.json (Claude Code), mcp.json in the Codex project root. It carries a session token — add it to .gitignore.

Known issues:

• argent init --help launches an interactive wizard regardless of the flag — use --yes to skip it, or read the package source for non-interactive flags.
• Re-running argent link against an already-linked URL without --yes reports "Already linked. No changes." and keeps the old token — every call then fails with 401 Unauthorized. Always pass --yes (as above) so a rotated token is actually written.