/**
 * Write a debug log line. Before `initLogger` is called, messages are buffered.
 * After init, writes synchronously to the log file (or is a no-op if disabled).
 *
 * @param tag Module name shown in brackets, e.g. "gitClient", "repoManager".
 * @param args Values joined with spaces into the log message.
 */
export declare function debug(tag: string, ...args: unknown[]): void;
/**
 * Initialize the logger. Must be called once after config is loaded.
 *
 * If enabled, opens the log file (`.digger/debug.log`), applies size-cap
 * truncation, writes a session header, and flushes any buffered messages.
 *
 * Always sets up error.log regardless of the debug flag.
 */
export declare function initLogger(opts: {
    workspaceRoot: string;
    debug: boolean;
}): void;
/**
 * Write an error log line to `.digger/error.log`.
 *
 * Works before `initLogger()` by falling back to `process.cwd()`.
 * Always writes regardless of the debug flag.
 */
export declare function error(tag: string, ...args: unknown[]): void;
/**
 * Write a critical error line to BOTH stderr AND `.digger/error.log` (when initialized).
 *
 * Use for crash/signal handlers in the server entry point — stderr is the resilient
 * channel visible to the MCP client and shell; `error.log` is additive persistence
 * when available. File write is best-effort and never throws.
 */
export declare function criticalError(tag: string, ...args: unknown[]): void;
/** Check whether debug logging is currently active. */
export declare function isDebugEnabled(): boolean;
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