Mintplex-Labs/anything-llm · critical · Error

No Mistral API key was set.

Error message

No Mistral API key was set.

What it means

Thrown by the MistralEmbedder constructor when process.env.MISTRAL_API_KEY is falsy. Unlike the local embedders, Mistral's endpoint is hardcoded (api.mistral.ai/v1) so only the API key is required. The openai SDK is pointed at Mistral with the key; without it requests would 401, so construction aborts immediately.

Source

Thrown at server/utils/EmbeddingEngines/mistral/index.js:4

class MistralEmbedder {
  constructor() {
    if (!process.env.MISTRAL_API_KEY)
      throw new Error("No Mistral API key was set.");

    const { OpenAI: OpenAIApi } = require("openai");
    this.openai = new OpenAIApi({
      baseURL: "https://api.mistral.ai/v1",
      apiKey: process.env.MISTRAL_API_KEY ?? null,
    });
    this.model = process.env.EMBEDDING_MODEL_PREF || "mistral-embed";
  }

  async embedTextInput(textInput) {
    const result = await this.embedChunks(
      Array.isArray(textInput) ? textInput : [textInput]
    );
    return result?.[0] || [];
  }

  async embedChunks(textChunks = []) {
    try {

View on GitHub (pinned to 526360e320)

Solutions

1. Set MISTRAL_API_KEY in .env to a valid key from console.mistral.ai
2. Restart AnythingLLM so the constructor re-reads env
3. Confirm the key is valid with a direct curl to api.mistral.ai/v1/embeddings

Example fix

// before
// MISTRAL_API_KEY unset

// after
MISTRAL_API_KEY=your-key-from-console.mistral.ai
EMBEDDING_MODEL_PREF=mistral-embed

function hasMistralKey(env = process.env) {
  return typeof env.MISTRAL_API_KEY === 'string' &&
         env.MISTRAL_API_KEY.trim().length > 0;
}
if (!hasMistralKey()) {
  throw new Error('Missing MISTRAL_API_KEY.');
}

function isMistralKey(v) {
  return typeof v === 'string' && /^[A-Za-z0-9_-]{20,}$/.test(v);
}

When it happens

Trigger: Selecting the Mistral embedding engine while MISTRAL_API_KEY is unset/empty; constructing `new MistralEmbedder()` before env load. The check on line 3 runs before the client is built.

Common situations: First-time Mistral setup; key rotated on the Mistral console but not in .env; key name typo (e.g. MISTRAL_KEY); secret not injected into the container/CI environment.

Related errors

• No OpenAI API key was set.
• No OpenRouter API key was set.
• LiteLLM must have a valid base path to use for the api.
• No embedding base path was set.
• No embedding model was set.

AI-assisted analysis of Mintplex-Labs/anything-llm@526360e320 (2026-08-13). Data as JSON: /api/errors/260068a13aa19266. Report an issue: GitHub.