/**
 * Extract a human-readable error string from an MCP isError result object.
 *
 * Shared utility — no side effects, no dependencies on other SDK modules —
 * so it can be imported from the neurolink.ts event loop, the telemetry
 * instrumentation (which loads earlier), and the MCP discovery layer without
 * creating circular imports. Any change to truncation or content-type parsing
 * must happen here and propagate to all three surfaces.
 */
export declare function extractMcpErrorText(raw: unknown): string;
/**
 * MCP tools signal failure by RETURNING `{ isError: true, ... }`, not throwing,
 * so execute()'s try/catch never sees it. Returns a capped status message for
 * failures (undefined for success) for the caller to set the span error level.
 *
 * Generic over input shape: accepts either a result object or a JSON-stringified
 * envelope (different providers hand back different shapes), mirroring
 * `extractMcpErrorText`. A non-JSON string has no `isError` field, so it is
 * correctly treated as "not an error" (→ undefined).
 *
 * Layered on `extractMcpErrorText`: this adds the `isError === true` gate and
 * the human-readable "MCP tool returned isError: …" prefix, while the shared
 * helper owns the content parsing and the 500-char cap. When `isError` is set
 * but no readable text is present, falls back to a generic message.
 */
export declare function extractMcpToolErrorMessage(result: unknown): string | undefined;
/**
 * Detect a tool result that REPORTS failure without throwing, for the native
 * loops' consecutive-failure breaker. Covers the two shapes NeuroLink itself
 * produces or forwards:
 * - MCP CallToolResult with `isError: true` (e.g. proxy-blocked tools) —
 *   delegated to {@link extractMcpToolErrorMessage}
 * - our own `{ error: "..." }` payloads
 * Plain strings are never classified (too false-positive-prone).
 * Returns the error text, or null when the result looks like a success.
 */
export declare function extractToolFailureText(result: unknown): string | null;