Mintplex-Labs/anything-llm · error · Error

LMStudio chat: ${this.model} is not valid or defined model f

Error message

LMStudio chat: ${this.model} is not valid or defined model for chat completion!

What it means

Thrown by LMStudioLLM.getChatCompletion when `this.model` is falsy at call time. This is a defensive re-check — the constructor already throws (error 232) if no model is set, so reaching this point with a falsy model is only possible if `this.model` was deleted or set to null/undefined after construction. The message interpolates this.model (which would be undefined/null/empty), producing a confusingly worded error.

Source

Thrown at server/utils/AiProviders/lmStudio/index.js:233

  /**
   * Parses and prepends reasoning from the response and returns the full text response.
   * Used for getChatCompletions to render thinking text if present in full response.
   * @param {Object} message - The message object from the LMStudio response.
   * @returns {string}
   */
  #parseReasoningFromResponse({ message }) {
    let textResponse = message?.content ?? "";
    if (
      !!message?.reasoning_content &&
      message.reasoning_content.trim().length > 0
    )
      textResponse = `<think>${message.reasoning_content}</think>${textResponse}`;
    return textResponse;
  }

  async getChatCompletion(messages = null, { temperature = 0.7 }) {
    if (!this.model)
      throw new Error(
        `LMStudio chat: ${this.model} is not valid or defined model for chat completion!`
      );

    const result = await LLMPerformanceMonitor.measureAsyncFunction(
      this.lmstudio.chat.completions.create({
        model: this.model,
        messages,
        temperature,
      })
    );

    if (
      !result.output.hasOwnProperty("choices") ||
      result.output.choices.length === 0
    )
      return null;

    return {

View on GitHub (pinned to 526360e320)

Solutions

Do not mutate `this.model` on the provider instance after construction — create a new provider with a different model instead.
If you see this error, investigate what code path deleted or nulled the model property after the constructor ran.
Re-instantiate the provider with the correct model preference to restore a valid state.

Example fix

// before — mutating model after construction (causes the error)
const llm = new LMStudioLLM(embedder, model);
llm.model = null; // don't do this
await llm.getChatCompletion(messages);

// after — create a new instance instead
const llm = new LMStudioLLM(embedder, newModel);
await llm.getChatCompletion(messages);

Defensive patterns

Strategy: type-guard

Validate before calling

function ensureModelSet(provider) {
  if (!provider.model || typeof provider.model !== 'string') {
    throw new Error('Provider model is not set — re-instantiate with a valid model.');
  }
  return true;
}

// Before calling getChatCompletion:
ensureModelSet(lmstudioProvider);
const result = await lmstudioProvider.getChatCompletion(messages);

Type guard

/** @param {object} provider @returns {provider is { model: string, getChatCompletion: Function }} */
function hasValidModel(provider) {
  return (
    typeof provider === 'object' &&
    provider !== null &&
    typeof provider.model === 'string' &&
    provider.model.trim().length > 0
  );
}

Try / catch

try {
  const result = await lmstudioProvider.getChatCompletion(messages, { temperature: 0.7 });
} catch (e) {
  if (e.message.includes('not valid or defined model')) {
    // Model was mutated post-construction; re-instantiate the provider.
    console.error('LMStudio model is missing — re-create the provider with a valid model.');
  } else {
    throw e;
  }
}

Prevention

Never mutate `this.model` on a provider instance after construction.
If you need a different model, construct a new provider instance.
Treat provider instances as immutable after construction.

When it happens

Trigger: Calling `lmstudioProvider.getChatCompletion(messages, { temperature })` after the provider was successfully constructed but `this.model` was subsequently mutated to a falsy value. In normal usage, this branch is unreachable because the constructor guarantees a truthy model.

Common situations: Code that manually clears or reassigns the model property on the provider instance after construction. A subclass or middleware that nullifies model properties. In practice, this error is rarely seen because the constructor guard catches the real problem earlier.

Related errors

AI-assisted analysis of Mintplex-Labs/anything-llm@526360e320 (2026-08-13). Data as JSON: /api/errors/2cf8a5e33af8e6e2. Report an issue: GitHub.