/**
 * Resolve the Forge project root.
 *
 * Returns CLAUDE_PROJECT_DIR when it points at a real directory; otherwise
 * falls back to process.cwd() and writes a warning to stderr.
 *
 * The existence check is load-bearing: a project-scoped `.mcp.json` may set
 * `CLAUDE_PROJECT_DIR` to an UNEXPANDED template token (e.g. the literal
 * "${projectRoot}") when the host doesn't substitute it. A non-empty-but-bogus
 * value would otherwise be trusted and flow straight into execFile's `cwd`,
 * where Node rejects the missing directory with a misleading
 * `spawn <node> ENOENT`. Validating here makes the server resilient to a
 * malformed env value and falls back to the (correct) launch cwd instead.
 */
export declare function resolveProjectRoot(): string;