k-skill-browser-runtime

Browser runtime adapter for k-skill packages, with platform-aware automatic provider selection.

Scope

• The recommended default is auto: macOS prefers Aside Browser, then BrowserOS, then Chrome/Chromium CDP. Other platforms preserve BrowserOS, Aside Browser, then Chrome/Chromium CDP.
• BrowserOS is used as a GUI/session browser over CDP, not as a headless backend, CAPTCHA bypass, login solver, payment solver, or stealth scraping browser.
• The browseros provider connects to a user-launched BrowserOS session. It never launches BrowserOS and never passes headless flags.
• The aside provider uses the public aside repl CLI surface. It does not rely on undocumented local ports or a private CDP endpoint.
• Site-specific navigation, parsing, and irreversible-boundary decisions stay in each skill.

Providers

| Provider | Default surface | Launches browser | Intended use | | --- | --- | --- | --- | | auto (default) | macOS: aside repl, BrowserOS 9100, Chrome 9222; other platforms: BrowserOS, Aside, Chrome | No | Platform-aware fallback order | | browseros | http://127.0.0.1:9100 | No | Force a user-launched BrowserOS GUI/session browser | | aside | aside repl | No | Force an available Aside Browser session through the documented CLI REPL | | chrome-cdp | http://127.0.0.1:9222 | No | Force a Chrome/Chromium CDP session | Unknown provider names fail closed with a typed UNKNOWN_PROVIDER error rather than silently falling back to BrowserOS.

Environment

• KSKILL_BROWSER_PROVIDER selects auto (default), browseros, aside, or chrome-cdp.
• KSKILL_BROWSEROS_CDP_URL overrides the BrowserOS CDP URL.
• KSKILL_CHROME_CDP_URL overrides the Chrome CDP URL.
• KSKILL_ASIDE_COMMAND overrides the Aside CLI command (default aside).

Lifecycle

For BrowserOS CDP and Chrome CDP sessions, disconnect automation clients instead of closing the browser application or persistent user profile. For Aside Browser sessions, close only tabs created by the adapter. Pre-existing user pages must not be closed.

Connect options

connect(options) selects and connects to a CDP endpoint. It supports dependency injection for tests:

• options.probe — false skips the CDP health probe; a function replaces the default probeCdp probe.
• options.connectLoader — function (cdpUrl, options) => browser replacing the default connectOverCDP path (which lazily loads playwright-core/playwright/rebrowser-playwright).
• options.chromiumLoader — function passed through to the default CDP loader for lazy chromium resolution and caching.

connect() probes CDP providers with <cdpUrl>/json/version before connecting. For Aside, it runs a safe aside repl probe that lists tabs without opening a page. Provider failures throw UNAVAILABLE; unknown providers throw UNKNOWN_PROVIDER.

Stop rules

The runtime exports typed stop reasons for manual handoff boundaries: authentication, CAPTCHA, payment, electronic signature, irreversible submit, blocked upstream responses, and provider unavailability.

Job runner

runJob({ url, steps, stopOn }) is a narrow declared-step runner. It executes ONLY caller-supplied step functions in declared order and never invents navigation, generates steps, or plans site behavior.

• steps — array of caller-supplied async functions ({ page, results }) => result. Empty/non-array steps returns { status: "no-steps", results: [] } without navigating.
• url — optional. When a URL is supplied AND at least one caller step exists, the runner performs a single page.goto(url, { waitUntil: "domcontentloaded" }) before the steps. No URL means no navigation.
• page — caller-supplied automation page (for example from getAutomationPage). Required only when url is supplied.
• stopOn — optional async callback ({ page, phase, url, step, index, results }) => stopReason | null invoked at phase boundaries: once before navigation (phase: "navigate") and once before each step (phase: "step", with index). A truthy stopReason short-circuits to { status: "stopped", stopReason, results } without bypassing manual handoff boundaries.

Returns { status, results } where status is "no-steps", "stopped", or "complete". Non-function steps throw a TypeError before any navigation or step execution.