/**
 * EmbedderMismatchError — one class, for every store that can tell.
 *
 * Pattern: shared refusal type (the `SqliteUnavailableError` precedent).
 * Role:    lib/, so no store adapter owns it and none has to import another.
 * Emits:   N/A.
 *
 * It lived inside `sqliteVector.ts` from 8.9.0 until 9.3.0, when a second and
 * a third store learned to make the same check. A duplicate class of the same
 * name would mean `catch (e) { if (e instanceof EmbedderMismatchError) }`
 * quietly depended on WHICH store threw — so there is exactly one, here, and
 * the stores import it.
 */
/**
 * Raised when a vector meets an index built by a different embedder.
 *
 * **This is the refusal that keeps a vector store honest.** Cosine similarity
 * between two different embedding spaces is not a weak signal — it is not a
 * signal at all, and it comes back as a confident number in the same 0-to-1
 * range as a real one. There is no threshold that separates them, and nothing
 * downstream can tell them apart. So the mismatch is refused where it happens,
 * on both sides:
 *
 *  - at **write**, so a second embedder's vectors never enter a namespace;
 *  - at **query**, so a swapped embedder never scores against the old ones.
 *
 * The named fix is an explicit re-index — delete the namespace and build it
 * again with one embedder, or point the retriever somewhere else. It is never a
 * fallback: silently ignoring the mismatch is the failure, and silently
 * re-embedding somebody's corpus is a bill they did not agree to.
 *
 * `problem` says which half is wrong. `'dimensions'` is arithmetically
 * impossible to score at all; `'model'` would score, and lie.
 */
export declare class EmbedderMismatchError extends Error {
    readonly code: "ERR_EMBEDDER_MISMATCH";
    /** The fingerprint the namespace was built with, `'<id>@<dims>'`. */
    readonly indexed: string;
    /** The fingerprint that just arrived. */
    readonly incoming: string;
    /** Which half disagrees. */
    readonly problem: 'dimensions' | 'model';
    /**
     * @param alternative the store-specific second way out, named in the
     *   message. A file-backed store says "point this store at a different
     *   file"; a service-backed one names its own unit of separation.
     */
    constructor(namespace: string, indexed: string, incoming: string, problem: EmbedderMismatchError['problem'], operation: 'write to' | 'search', alternative?: string);
}
/** An embedder fingerprint, split into the two halves that decide separately. */
export interface Fingerprint {
    readonly id?: string;
    readonly dims: number;
}
/** `'<id>@<dims>'`, with `'?'` for an embedder that did not name itself. */
export declare function fingerprintText(fp: Fingerprint): string;
/** Parse the `'<id>@<dims>'` form back into its halves. */
export declare function parseFingerprint(text: string): Fingerprint;
/**
 * What, if anything, makes these two incompatible.
 *
 * Dimensions always decide: two lengths cannot be compared at all. Model ids
 * decide only when BOTH sides named themselves — an anonymous vector is not
 * evidence of a different embedder, and refusing on absence would break every
 * caller who never passed an `embedderId`, which is most of them.
 */
export declare function fingerprintConflict(stored: Fingerprint, incoming: Fingerprint): 'dimensions' | 'model' | null;