@kindgi/embedding

Embedding provider interface and an in-memory provider registry for Kindgi. An embedding provider turns text into a fixed-length vector; adapters implement EmbeddingProvider, a deployment registers them once at boot, and consumers such as semantic search in @kindgi/memory and agent retrieval in @kindgi/agents take the registry and resolve a provider from it instead of receiving one per call.

Purpose

Keep vectors consistent with the model that produced them. The registry is keyed by describe().model, the identifier storage layers use to tag stored embeddings, so a model can only be registered once: silently replacing the implementation behind a model that already has indexed vectors would corrupt the index. dimensions() must equal the length of every embed() result, so callers can size vector indexes at boot. Resolution without an explicit model succeeds only when exactly one provider is registered.

Exports

• EmbeddingProvider — the adapter interface:
  • embed(text) — returns a Promise<Float32Array>.
  • dimensions() — vector length; must match every embed() result.
  • describe() — { name, version, model }. model is the stable storage key; never rename it across versions.
• createEmbeddingProviderRegistry(seed?) — builds an in-memory registry, preserving registration order. A duplicate model in seed throws synchronously.
• EmbeddingProviderRegistry — the registry interface (process-wide, not tenant-scoped):
  • register(provider) — Result<void, DuplicateEmbeddingProviderError>; rejects a model that is already registered.
  • resolve(model?) — the provider for model; with no argument, the sole registered provider.
  • getByModel(model), has(model), list(), size().
• EmbeddingError — union of the typed errors, discriminated by code:
  • NoEmbeddingProviderError (no-embedding-provider) — no model given and nothing is registered.
  • UnknownEmbeddingModelError (unknown-embedding-model) — model is not registered; known lists the registered models.
  • AmbiguousDefaultProviderError (ambiguous-default-provider) — no model given and more than one is registered; known lists them.
  • DuplicateEmbeddingProviderError (duplicate-embedding-provider) — returned by register.

Example

import { createEmbeddingProviderRegistry, type EmbeddingProvider } from '@kindgi/embedding';

// An adapter over a self-hosted embedding endpoint.
function httpEmbeddingProvider(endpoint: string, model: string, dims: number): EmbeddingProvider {
  return {
    async embed(text) {
      const res = await fetch(endpoint, {
        method: 'POST',
        headers: { 'content-type': 'application/json' },
        body: JSON.stringify({ model, input: text }),
      });
      if (!res.ok) throw new Error(`embedding request failed: ${res.status}`);
      const { embedding } = (await res.json()) as { embedding: number[] };
      if (embedding.length !== dims) throw new Error(`expected ${dims} dimensions, got ${embedding.length}`);
      return Float32Array.from(embedding);
    },
    dimensions: () => dims,
    describe: () => ({ name: 'http-embedding', version: '1.0.0', model }),
  };
}

// Built once at boot; a duplicate model in the seed throws here.
const registry = createEmbeddingProviderRegistry([
  httpEmbeddingProvider('http://localhost:8080/embed', 'acme-embed-v1', 384),
]);

// No model given: resolves the sole registered provider.
const resolved = registry.resolve();
if (resolved.kind === 'err') throw new Error(`${resolved.error.code}: ${resolved.error.message}`);
const vector = await resolved.value.embed('quarterly revenue by region');
console.log(vector.length === resolved.value.dimensions()); // true

Non-goals

• No bundled provider. Semantic embedding is opt-in; register an adapter at boot. The Kindgi runtime offers a self-hosted local-model provider.
• No replacement or re-dimensioning in place. To change a model's dimensions, register it under a new model and migrate existing vectors separately.
• No per-tenant model policy. The registry is process-global; which model a tenant may use is a separate concern.
• No vector storage or similarity search. Storing and querying vectors belongs to the consuming layer, such as @kindgi/memory.

Related

• @kindgi/memory — searchBySemantic takes an EmbeddingProviderRegistry and an optional embeddingModel.
• @kindgi/agents — runRetrievals takes the registry (RetrievalBindings.embeddingRegistry) for semantic retrieval intents.
• @kindgi/types — Result.