/**
 * Canvas extension discovery.
 *
 * Design: `docs/canvas-extensions-design.md` §4.1, §4.3. GitHub's
 * `docs/extensions.md` is specific: the CLI "scans `.github/extensions/`
 * (project) and the user's copilot config extensions directory for
 * subdirectories containing `extension.mjs`", the entry file is required and must
 * be named `extension.mjs`, and only ES modules are supported. All 23 extensions
 * in `github/awesome-copilot` comply.
 *
 * So discovery keys off `<dir>/extension.mjs` and nothing else. In particular it
 * does not read `package.json`: 3 of those 23 extensions ship without one, none
 * ships `node_modules`, and where a `package.json` does exist its `main` is
 * always `extension.mjs` anyway. Keying off it would add a failure mode without
 * adding information.
 *
 * The extension id is the directory name, matching how the catalog and the
 * Copilot app refer to extensions (`pr-artifact-explorer`).
 *
 * Some extensions also carry a `copilot-extension.json`, but it is neither
 * required nor informative: 8 of the 23 catalog extensions have one, every
 * instance holds exactly `{ name, version }`, and `name` always equals the
 * directory name. Reading it would add a parse and a disagreement case without
 * telling us anything the directory name does not.
 */
/** Required entry file name. */
export declare const CANVAS_ENTRY_FILE = "extension.mjs";
/** Where a canvas extension came from, in precedence order. */
export type CanvasScope = "agents" | "project" | "user";
/** Directory searched for canvas extensions. */
export interface CanvasSearchRoot {
    dir: string;
    scope: CanvasScope;
}
/** One discovered extension. */
export interface DiscoveredCanvasExtension {
    /** Directory name, used as the provider identifier. */
    id: string;
    /** Absolute path to the extension directory. */
    dir: string;
    /** Absolute path to `extension.mjs`. */
    entry: string;
    scope: CanvasScope;
}
/**
 * Search roots in precedence order. `.agents/` first per
 * `docs/plugin-format-mapping.md` §0; the Copilot conventions follow as
 * compatibility inputs.
 *
 * `.github/extensions/` travels with a clone, so anything found there is subject
 * to the workspace-trust gate before it is ever forked (design doc §5). Discovery
 * itself is read-only and always safe to run.
 */
export declare function canvasSearchRoots(cwd: string, homeDir: string): CanvasSearchRoot[];
/**
 * Discover canvas extensions across `roots`, then append `extra`. First wins on
 * an id collision, so a project-local extension shadows a same-named user-scope
 * one — and anything a person placed in a search root by hand shadows a
 * same-named canvas that arrived inside a package.
 *
 * `extra` is how plugin-shipped canvases join the same list (see
 * `plugin-canvases.ts`): a plugin's canvas directories are named by its manifest
 * rather than by their position under a search root, so they cannot be expressed
 * as a root — but once resolved they are ordinary discovered extensions, and
 * every consumer downstream is better off not knowing the difference.
 */
export declare function discoverCanvasExtensions(roots: CanvasSearchRoot[], extra?: readonly DiscoveredCanvasExtension[]): DiscoveredCanvasExtension[];
//# sourceMappingURL=discovery.d.ts.map