/**
 * Code Symbol Embeddings — semantic search via transformers.js.
 *
 * Provides text-to-vector embedding for semantic code search.
 * Uses @huggingface/transformers with snowflake-arctic-embed-xs (384-dim)
 * as default, with pluggable provider interface.
 *
 * Gracefully degrades to BM25-only search when embeddings unavailable.
 *
 * @task T1058 EP1-T2
 */
/**
 * Contract for code embeddings providers.
 * Can be replaced via CLEO_EMBEDDINGS_PROVIDER env var.
 */
export interface CodeEmbeddingProvider {
    /**
     * Convert code text into a fixed-dimension vector.
     * Text should be symbol name + docstring for best results.
     */
    embed(text: string): Promise<Float32Array>;
    /**
     * Vector dimensionality (384 for snowflake-arctic-embed-xs).
     * Must match nexus_embeddings vec0 table schema.
     */
    readonly dimensions: number;
    /**
     * Whether the provider is ready to produce embeddings.
     * Returns false if model loading failed or dependencies unavailable.
     */
    isAvailable(): boolean;
}
/** Standard vector dimension for code embeddings (matches nexus schema). */
export declare const CODE_EMBEDDING_DIMENSIONS = 384;
/**
 * Register a code embeddings provider.
 *
 * @throws Error if provider dimensions do not match CODE_EMBEDDING_DIMENSIONS
 */
export declare function setCodeEmbeddingProvider(provider: CodeEmbeddingProvider): void;
/** Get the currently registered code embeddings provider. */
export declare function getCodeEmbeddingProvider(): CodeEmbeddingProvider | null;
/** Clear the current code embeddings provider (useful for testing). */
export declare function clearCodeEmbeddingProvider(): void;
/** Check if code embeddings are available. */
export declare function isCodeEmbeddingAvailable(): boolean;
/**
 * Embed code text using the registered provider.
 *
 * @param text - Symbol name + docstring or full source
 * @returns Float vector or null if embeddings unavailable
 */
export declare function embedCodeSymbol(text: string): Promise<Float32Array | null>;
/**
 * Transformer.js-backed code embeddings provider.
 *
 * Uses Xenova/snowflake-arctic-embed-xs (384-dim, 85MB).
 * Lazy-loads @huggingface/transformers on first use.
 *
 * @internal
 */
export declare class TransformersCodeEmbeddingProvider implements CodeEmbeddingProvider {
    readonly dimensions = 384;
    private extractor;
    private initPromise;
    private initError;
    isAvailable(): boolean;
    /**
     * Initialize the transformer model (lazy-loaded).
     *
     * @throws Error if @huggingface/transformers unavailable or model fails to load
     */
    ensureInitialized(): Promise<void>;
    /**
     * Internal: load the transformers pipeline.
     *
     * @throws Error if module not found or model download fails
     */
    private initializeExtractor;
    /**
     * Embed code symbol name + docstring.
     *
     * @param text - Symbol name or name + docstring
     * @returns 384-dim vector
     * @throws Error if model unavailable or extraction fails
     */
    embed(text: string): Promise<Float32Array>;
}
/**
 * Initialize the default code embeddings provider.
 *
 * Uses @huggingface/transformers with snowflake-arctic-embed-xs model.
 * Gracefully degrades if package unavailable (returns null).
 *
 * @returns true if initialized successfully, false if unavailable
 *
 * @task T1058
 */
export declare function initDefaultCodeEmbeddingProvider(): Promise<boolean>;
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