/**
 * Load the ZPL user API key from (in priority order):
 *
 *   1. ~/.zpl/config.toml  — written by `npx zpl-engine-mcp setup` device flow.
 *      Preferred because a config file is not logged by Claude Desktop / Cursor,
 *      is per-user (not per-project), and survives MCP client updates.
 *
 *   2. process.env.ZPL_API_KEY / ZPL_ENGINE_KEY — legacy path, still supported
 *      so existing users don't break. `env-keys.ts::resolveZplApiKey()` is the
 *      single source of truth for env-name lookup.
 *
 * Returns the raw key string as-is (no format validation) plus a tag for
 * debugging / first-run messages. Format validation lives in `index.ts` where
 * the user-visible error text is assembled.
 *
 * Never logs the key. File read is best-effort — if the file exists but is
 * malformed, we warn to stderr and fall through to the env var so the user
 * still gets *some* way to run the MCP.
 */
export type ApiKeySource = "config" | "env" | "none";
export interface LoadedApiKey {
    key: string;
    source: ApiKeySource;
}
/** Absolute path to the config.toml the `setup` subcommand writes. */
export declare function getConfigPath(): string;
/**
 * Parse the single `api_key = "..."` line out of our config.toml.
 * We deliberately don't pull in a TOML library — the file is written by our
 * own `setup` command with a known shape, and the only value the MCP needs
 * at startup is `api_key`. Keeps the dep tree at 1 package.
 *
 * Accepts both double and single quotes. Comments (#) and whitespace OK.
 * Returns undefined on any parse failure — caller decides what to do.
 */
export declare function parseApiKeyFromToml(raw: string): string | undefined;
/** Read a single named string field from our minimal config.toml. */
export declare function parseTomlString(raw: string, field: string): string | undefined;
/**
 * Best-effort plan lookup from local config.
 *
 * Engine doesn't expose a /api/me endpoint yet (TODO M3.x), so we can't
 * auto-detect plan from the server. v3.7.2 adds `plan` to config.toml so
 * users can set it once after setup and zpl_quota / zpl_alert estimates
 * stay accurate. Precedence: env var > config.toml > "free".
 */
export declare function loadPlan(): Promise<string>;
/**
 * Load the API key. v4.1.7 (audit 2026-05-13): aligned precedence with
 * the CLI — ENV wins over file. Previously MCP did file-wins-over-env,
 * which meant a dual-tool user with `ZPL_API_KEY=staging` in shell and a
 * prod key in `~/.zpl/config.toml` saw CLI hit staging but MCP hit prod.
 * Same machine, same file, same env var, different behaviour. v4.1.7
 * flips MCP so both tools resolve identically: env first (12-factor
 * standard), config.toml as fallback.
 *
 * Migration impact: zero for normal users (most have ONE source). Users
 * who relied on file-wins must `unset ZPL_API_KEY` before running MCP
 * via `npx`. The setup wizard still writes config.toml first; that path
 * is unchanged.
 */
export declare function loadApiKey(): Promise<LoadedApiKey>;