chroma-core/chroma · error · ChromaValueError

Config is missing a required field

Error message

Config is missing a required field

What it means

Thrown by the static buildFromConfig() of ChromaCloudQwenEmbeddingFunction with a ChromaValueError when the config object being deserialized lacks model or task. Chroma stores embedding-function configs and rebuilds functions from them (e.g., when a collection is re-opened); those two fields are required to reconstruct the Qwen function, so their absence is a config corruption or schema drift signal.

Source

Thrown at clients/new-js/packages/ai-embeddings/chroma-cloud-qwen/src/index.ts:196

        throw new Error(`Error calling Chroma Embedding API: ${error}`);
      }
    }
  }

  public defaultSpace(): EmbeddingFunctionSpace {
    return "cosine";
  }

  public supportedSpaces(): EmbeddingFunctionSpace[] {
    return ["cosine", "l2", "ip"];
  }

  public static buildFromConfig(
    config: ChromaCloudQwenConfig,
    client?: ChromaClient,
  ): ChromaCloudQwenEmbeddingFunction {
    if (config.model === undefined || config.task === undefined) {
      throw new ChromaValueError("Config is missing a required field");
    }

    // Deserialize instructions dict from string keys to enum keys (if needed)
    // The config.instructions will have string keys like "nl_to_code" and "documents"
    // We need to convert these to the enum values for proper runtime usage
    let deserializedInstructions: ChromaCloudQwenEmbeddingInstructions;

    if (config.instructions) {
      deserializedInstructions = {} as ChromaCloudQwenEmbeddingInstructions;
      for (const [taskKey, targets] of Object.entries(config.instructions)) {
        deserializedInstructions[taskKey] = {} as Record<
          ChromaCloudQwenEmbeddingTarget,
          string
        >;
        for (const [targetKey, instruction] of Object.entries(targets)) {
          // targetKey is the enum value string like "documents" or "query"
          const targetEnum = targetKey as ChromaCloudQwenEmbeddingTarget;
          deserializedInstructions[taskKey][targetEnum] = instruction;

View on GitHub (pinned to aecdd12c8a)

Solutions

1. Include both required fields: config.model (a ChromaCloudQwenEmbeddingModel value) and config.task (string or null).
2. Build configs from a live instance: new ChromaCloudQwenEmbeddingFunction(...).getConfig() round-trips every required field.
3. If loading stored configs from an older version, backfill model/task before calling buildFromConfig.

Example fix

// before
const ef = ChromaCloudQwenEmbeddingFunction.buildFromConfig({
  api_key_env_var: "CHROMA_API_KEY",
}); // no model/task

// after
const ef = ChromaCloudQwenEmbeddingFunction.buildFromConfig({
  model: ChromaCloudQwenEmbeddingModel.QWEN3_EMBEDDING_0p6B,
  task: null,
  api_key_env_var: "CHROMA_API_KEY",
});

function isCompleteQwenConfig(c: Partial<ChromaCloudQwenConfig>): c is ChromaCloudQwenConfig {
  return c.model !== undefined && c.task !== undefined;
}

if (!isCompleteQwenConfig(storedConfig)) {
  throw new Error("Stored Qwen config is missing model or task; backfill before rebuild");
}
const ef = ChromaCloudQwenEmbeddingFunction.buildFromConfig(storedConfig);

function isCompleteQwenConfig(c: unknown): c is ChromaCloudQwenConfig {
  if (typeof c !== "object" || c === null) return false;
  const cfg = c as Record<string, unknown>;
  return typeof cfg.model === "string" && (cfg.task === null || typeof cfg.task === "string");
}

When it happens

Trigger: Passing a hand-built config to buildFromConfig({ config }) with only api_key_env_var or instructions; loading a persisted collection whose stored EF config was written by an older library version without model/task; YAML/JSON config file missing the fields.

Common situations: Migrating between chromadb JS versions where the config schema changed; manually crafting EF configs instead of using getConfig() from a live instance; truncated config stores.

Related errors

• The model name cannot be changed after initialization.
• The task type cannot be changed after initialization.
• Changing the URL is not allowed.
• Cannot change model name.
• Model cannot be updated

AI-assisted analysis of chroma-core/chroma@aecdd12c8a (2026-08-16). Data as JSON: /api/errors/b6ed7e5b74c57934. Report an issue: GitHub.