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Use global flags to control CLI behavior consistently across commands, especially for telemetry and machine-readable output. Extension.js telemetry is intentionally anonymous and privacy-safe. It sends at most two event types (command_executed and command_failed). Each event carries command, success, and version, and create runs add template and source. Coarse environment facts ride along (os, arch, node_major, is_ci, is_source_build).

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Global flag capabilities

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Global options

--format is a deprecated alias for --output. It still works, and the CLI prints a deprecation warning on stderr once per run. The same applies to the older --wait-format alias. Flag misuse fails with a stable code: --no-reload outside dev and --no-browser outside dev/start/preview fail with E_FLAG_NOT_SUPPORTED_HERE. The removed --no-runner flag fails with E_REMOVED_FLAG, use --no-browser instead. You can also set no-browser mode per command in extension.config.js with commands.<command>.noBrowser: true. The CLI flag wins when both are present. --no-browser is the flag that stops the browser from launching. Do not confuse it with --no-open, which dev, start, and preview each declare. Under --no-open the browser still launches and loads your extension. Only the tab Extension.js would open for it is skipped. Full comparison on the dev page.

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Optional boolean flags

Flags documented as [boolean] (for example, --polyfill, --zip, --zip-source, --silent, --wait, --install) accept an explicit value, so you can enable or disable them without a separate --no-* flag:
  • A bare flag enables it: extension dev --polyfill
  • false, 0, no, and off disable it: extension dev --polyfill false
  • true, 1, and yes enable it: extension build --zip true
This is useful for overriding a default set in extension.config.* from the command line, or for passing a computed value in a script (extension build --zip "$SHOULD_ZIP").

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Telemetry opt-out options

You can disable telemetry in three ways (listed in precedence order):
Set EXTENSION_TELEMETRY_DISABLED=1 in continuous integration (CI) when policy requires no telemetry across all runs.

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Practical examples

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Disable telemetry for a CI build

Use this when policy requires explicitly disabling telemetry for automation runs.

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Generate machine-readable help for tooling

Use this for AI tooling, wrappers, or scripts that parse command help output.

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Keep readable help output for local debugging

Use pretty mode when you want assistant-friendly output that still reads well in terminal sessions.

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Behavior notes

  • The CLI parses global flags before command-specific options.
  • See docs/TELEMETRY.md in the Extension.js repository and Telemetry and privacy for telemetry behavior and privacy details.
  • Use extension telemetry status to check the current consent state.
  • Command pages document command-specific flags separately.
  • You can combine global flags with command-specific options.
  • Automated tools (AI assistants and CI scripts) should read command readiness from dist/extension-js/<browser>/ready.json, not from terminal log parsing. See ready.json.

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Next steps