MCP tool protocol

@hover-dev/mcp is a standard Model Context Protocol server. Your coding agent connects to it over stdio; the server exposes a small set of tools and one prompt. Add it once and your agent gets both:

npm i -g @hover-dev/mcp
claude mcp add hover -- hover-mcp

Configuration (env)

The server reads its target from the environment its host sets:

Variable	Default	Purpose
`HOVER_TARGET`	`http://localhost:5173`	The app under test — the origin the engine matches a CDP tab against.
`HOVER_CDP_PORT`	`9222`	The debug Chrome's remote-debugging port.
`HOVER_PROJECT_ROOT`	`process.cwd()`	Where `__vibe_tests__/` and `.hover/` are written.

Tools

Every tool returns a short text result (✓ / ✗) and never throws — a failed locate or action becomes a ✗ message the calling agent can react to, not a transport error.

Tool	Input	Purpose
`browser_navigate`	`{ url }`	Open a URL in the app under test.
`browser_snapshot`	`{}`	Return the page as an ARIA snapshot (role + accessible-name tree). Call before actuating.
`click_control`	grounded target	Click a control by `role+name → testId → text`.
`fill_control`	grounded target `+ { value }`	Type a value into a textbox / field.
`select_control`	grounded target `+ { value }`	Choose an option in a `<select>`.
`check_control`	grounded target `+ { checked? }`	Check / uncheck a checkbox or radio.
`assert_visible`	grounded target	Assert visible now — captures `expect(...).toBeVisible()`.
`recall_business_knowledge`	`{}`	Recall what earlier runs learned about this app.
`record_fact`	`{ title, rule, type? }`	Persist a durable business rule (rules only — no secrets / PII).
`crystallize_spec`	`{ name, description? }`	Save the recorded grounded flow as a plain Playwright spec in `__vibe_tests__/`.

The grounded target shape

{
  role?: string;    // ARIA role from the snapshot — pair with name
  name?: string;    // accessible name, exactly as shown — pair with role
  testId?: string;  // a data-testid, if no clean role+name exists
  text?: string;    // real visible text — last resort
  within?: { role: string; name: string };  // scope to a container first
}

`record_fact` types

type is one of business-rule (default), expected-behavior, validation, or access-policy. The fact is written under .hover/memory/ — see your app's test knowledge.

Prompt

Prompt	Args	Purpose
`test_app`	`{ scope? }`	The phased, scale-aware authoring workflow. Claude Code surfaces it as `/mcp__hover__test_app`. Omit `scope` to cover the whole app, or pass an area / flow to focus on.

For the authoritative definitions see packages/mcp/src/mcp/server.ts and the controller it wraps.