import type { BaseMessage } from '@langchain/core/messages';
/**
 * Cached tool discovery entry.
 * Stores the tool name and the message index where it was discovered,
 * enabling efficient lookups without re-parsing conversation history.
 */
export interface ToolDiscoveryEntry {
    /** The tool name that was discovered */
    toolName: string;
    /** Message index in conversation history where discovery occurred */
    discoveredAtIndex: number;
}
/**
 * ToolDiscoveryCache provides a run-scoped cache of tool search results.
 *
 * Problem: Without caching, every LLM iteration re-parses the full message
 * history via extractToolDiscoveries() to find tool_search results. In long
 * conversations with many tool iterations, this is redundant work.
 *
 * Solution: Cache discovered tool names by message index. On each iteration,
 * only scan messages AFTER the last scanned index. Already-seen discoveries
 * are returned from cache instantly.
 *
 * This mirrors the pattern used by VS Code Copilot Chat where tool search
 * results from prior turns are cached to avoid re-discovery.
 *
 * @example
 * ```ts
 * const cache = new ToolDiscoveryCache();
 *
 * // First call: scans all messages
 * const newTools = cache.getNewDiscoveries(messages);
 * // Returns: ['web_search', 'file_read']
 *
 * // Second call (3 new messages added): only scans new messages
 * const moreTools = cache.getNewDiscoveries(messages);
 * // Returns: ['code_exec'] (only newly discovered)
 * ```
 */
export declare class ToolDiscoveryCache {
    /** Set of all discovered tool names (deduped) */
    private _discoveredTools;
    /** Last message index that was scanned */
    private _lastScannedIndex;
    /**
     * Scan messages for new tool_search results since the last scan.
     * Only processes messages after `_lastScannedIndex` to avoid redundant work.
     *
     * @param messages - Full conversation message array
     * @returns Array of newly discovered tool names (not previously cached)
     */
    getNewDiscoveries(messages: BaseMessage[]): string[];
    /**
     * Returns all tool names discovered so far (across all scans).
     */
    getAllDiscoveredTools(): string[];
    /**
     * Check if a specific tool has been discovered.
     */
    has(toolName: string): boolean;
    /**
     * Number of unique tools discovered.
     */
    get size(): number;
    /**
     * Reset the cache (e.g., on graph reset).
     */
    reset(): void;
    /**
     * Seed the cache with previously known tool names (e.g., from prior conversation turns).
     * Does not affect _lastScannedIndex — the next getNewDiscoveries call will still
     * scan all messages from the beginning.
     *
     * @param toolNames - Tool names to pre-seed into the cache
     */
    seed(toolNames: string[]): void;
}