Mistral AI Common Errors

Overview

Quick reference for the most common Mistral AI errors and their solutions.

Prerequisites

• Mistral AI SDK installed

• API credentials configured

• Access to error logs

Instructions

Step 1: Identify the Error

Check error message, status code, and request ID in your logs or console.

Step 2: Find Matching Error Below

Match your error to one of the documented cases.

Step 3: Apply Solution

Follow the solution steps for your specific error.

Output

• Identified error cause

• Applied fix

• Verified resolution

Error Handling

401 Unauthorized - Authentication Failed

Error Message:

Error: Authentication failed. Invalid API key. Status: 401 # HTTP 401 Unauthorized

Cause: API key is missing, expired, or invalid.

Solution:

set -euo pipefail

Verify API key is set

echo $MISTRAL_API_KEY

Test API key

curl -H "Authorization: Bearer ${MISTRAL_API_KEY}"
https://api.mistral.ai/v1/models

Code Fix:

// Ensure API key is loaded const apiKey = process.env.MISTRAL_API_KEY; if (!apiKey) { throw new Error('MISTRAL_API_KEY is not set'); } const client = new Mistral({ apiKey });

429 Too Many Requests - Rate Limited

Error Message:

Error: Rate limit exceeded. Please retry after X seconds. Status: 429 # HTTP 429 Too Many Requests Headers: Retry-After: 60

Cause: Too many requests in a short period.

Solution: Implement exponential backoff. See mistral-rate-limits skill.

// Quick fix: Add delay and retry async function withRetry<T>(fn: () => Promise<T>, maxRetries = 3): Promise<T> { for (let i = 0; i < maxRetries; i++) { try { return await fn(); } catch (error: any) { if (error.status === 429 && i < maxRetries - 1) { # HTTP 429 Too Many Requests const retryAfter = parseInt(error.headers?.['retry-after'] || '60'); console.log(Rate limited. Waiting ${retryAfter}s...); await new Promise(r => setTimeout(r, retryAfter * 1000)); # 1000: 1 second in ms } else { throw error; } } } throw new Error('Max retries exceeded'); }

400 Bad Request - Invalid Parameters

Error Message:

Error: Invalid request. Check your parameters. Status: 400 # HTTP 400 Bad Request {"message": "Invalid model: mistral-ultra"}

Cause: Invalid model name, malformed messages, or incorrect parameters.

Solution:

// Valid model names const VALID_MODELS = [ 'mistral-large-latest', 'mistral-medium-latest', // Deprecated - use small or large 'mistral-small-latest', 'open-mistral-7b', 'open-mixtral-8x7b', 'mistral-embed', ] as const;

// Validate before request function validateRequest(model: string, messages: any[]) { if (!VALID_MODELS.includes(model as any)) { throw new Error(Invalid model: ${model}); } if (!messages || messages.length === 0) { throw new Error('Messages array cannot be empty'); } for (const msg of messages) { if (!['system', 'user', 'assistant', 'tool'].includes(msg.role)) { throw new Error(Invalid role: ${msg.role}); } } }

413 Payload Too Large - Context Exceeded

Error Message:

Error: Request too large. Maximum context length exceeded. Status: 413 # 413 = configured value

Cause: Too many tokens in the request.

Solution:

// Truncate conversation history function truncateMessages(messages: Message[], maxTokens = 30000): Message[] { # 30000: 30 seconds in ms // Keep system message const systemMsg = messages.find(m => m.role === 'system'); const otherMsgs = messages.filter(m => m.role !== 'system');

// Estimate ~4 chars per token let tokenEstimate = systemMsg ? systemMsg.content.length / 4 : 0; const truncated: Message[] = systemMsg ? [systemMsg] : [];

// Add messages from most recent for (let i = otherMsgs.length - 1; i >= 0; i--) { const msgTokens = otherMsgs[i].content.length / 4; if (tokenEstimate + msgTokens > maxTokens) break; tokenEstimate += msgTokens; truncated.unshift(otherMsgs[i]); }

return truncated; }

500/503 Server Error - Mistral Service Issue

Error Message:

Error: Internal server error Status: 500/503 # 503: HTTP 500 Internal Server Error

Cause: Mistral AI service experiencing issues.

Solution:

set -euo pipefail

Check Mistral status

curl -s https://status.mistral.ai/ | head -20

Implement circuit breaker

class CircuitBreaker { private failures = 0; private lastFailure?: Date; private readonly threshold = 5; private readonly resetTimeout = 60000; // 1 minute # 60000: 1 minute in ms

async call<T>(fn: () => Promise<T>): Promise<T> { if (this.isOpen()) { throw new Error('Circuit breaker is open'); }

try {
  const result = await fn();
  this.failures = 0;
  return result;
} catch (error: any) {
  if (error.status >= 500) {  # HTTP 500 Internal Server Error
    this.failures++;
    this.lastFailure = new Date();
  }
  throw error;
}

}

private isOpen(): boolean { if (this.failures < this.threshold) return false; const elapsed = Date.now() - (this.lastFailure?.getTime() || 0); return elapsed < this.resetTimeout; } }

Network Timeout

Error Message:

Error: Request timeout after 30000ms

Cause: Network connectivity or server latency issues.

Solution:

// Increase timeout const client = new Mistral({ apiKey: process.env.MISTRAL_API_KEY, timeout: 60000, // 60 seconds # 60000: 1 minute in ms });

// For streaming, use longer timeout const client = new Mistral({ apiKey: process.env.MISTRAL_API_KEY, timeout: 120000, // 2 minutes for long responses # 120000 = configured value });

Invalid Tool/Function Schema

Error Message:

Error: Invalid tool definition {"message": "function.parameters must be a valid JSON Schema"}

Cause: Malformed function calling schema.

Solution:

// Correct tool schema const tool = { type: 'function', function: { name: 'get_weather', // lowercase, underscores description: 'Get weather for a location', parameters: { type: 'object', properties: { location: { type: 'string', // Valid JSON Schema types description: 'City name', }, }, required: ['location'], // Array of required property names }, }, };

Quick Diagnostic Commands

set -euo pipefail

Check API connectivity

curl -I https://api.mistral.ai/v1/models
-H "Authorization: Bearer ${MISTRAL_API_KEY}"

List available models

curl https://api.mistral.ai/v1/models
-H "Authorization: Bearer ${MISTRAL_API_KEY}" | jq '.data[].id'

Check local configuration

env | grep MISTRAL

Test basic chat

curl https://api.mistral.ai/v1/chat/completions
-H "Content-Type: application/json"
-H "Authorization: Bearer ${MISTRAL_API_KEY}"
-d '{ "model": "mistral-small-latest", "messages": [{"role": "user", "content": "Hello"}] }'

Escalation Path

• Collect evidence with mistral-debug-bundle

• Check Mistral status page: https://status.mistral.ai/

• Contact support via Discord or email

Resources

• Mistral AI Status Page

• Mistral AI Discord

• Mistral AI API Reference

Next Steps

For comprehensive debugging, see mistral-debug-bundle .

Examples

Basic usage: Apply mistral common errors to a standard project setup with default configuration options.

Advanced scenario: Customize mistral common errors for production environments with multiple constraints and team-specific requirements.