Mistral AI Local Dev Loop

Overview

Set up a fast, reproducible local development workflow for Mistral AI integrations.

Prerequisites

Completed mistral-install-auth setup
Node.js 18+ with npm/pnpm
Code editor with TypeScript support
Git for version control

Instructions

Step 1: Create Project Structure

my-mistral-project/
├── src/
│   ├── mistral/
│   │   ├── client.ts       # Mistral client wrapper
│   │   ├── config.ts       # Configuration management
│   │   ├── types.ts        # TypeScript types
│   │   └── utils.ts        # Helper functions
│   └── index.ts
├── tests/
│   ├── unit/
│   │   └── mistral.test.ts
│   └── integration/
│       └── mistral.integration.test.ts
├── .env.local              # Local secrets (git-ignored)
├── .env.example            # Template for team
├── tsconfig.json
├── vitest.config.ts
└── package.json

Step 2: Configure Environment

bash

# Create environment template
cat > .env.example << 'EOF'
MISTRAL_API_KEY=your-api-key-here
MISTRAL_MODEL=mistral-small-latest
LOG_LEVEL=debug
EOF

# Copy for local development
cp .env.example .env.local

# Add to .gitignore
echo '.env.local' >> .gitignore
echo '.env' >> .gitignore

Step 3: Setup Hot Reload

package.json

json

{
  "scripts": {
    "dev": "tsx watch src/index.ts",
    "build": "tsc",
    "test": "vitest",
    "test:watch": "vitest --watch",
    "test:integration": "vitest run --config vitest.integration.config.ts",
    "lint": "eslint src --ext .ts",
    "typecheck": "tsc --noEmit"
  },
  "devDependencies": {
    "@types/node": "^20.0.0",
    "dotenv": "^16.0.0",
    "tsx": "^4.0.0",
    "typescript": "^5.0.0",
    "vitest": "^1.0.0"
  },
  "dependencies": {
    "@mistralai/mistralai": "^1.0.0"
  }
}

tsconfig.json

json

{
  "compilerOptions": {
    "target": "ES2022",
    "module": "NodeNext",
    "moduleResolution": "NodeNext",
    "strict": true,
    "esModuleInterop": true,
    "skipLibCheck": true,
    "outDir": "dist",
    "rootDir": "src"
  },
  "include": ["src/**/*"],
  "exclude": ["node_modules", "dist"]
}

Step 4: Configure Testing

vitest.config.ts

typescript

import { defineConfig } from 'vitest/config';

export default defineConfig({
  test: {
    globals: true,
    environment: 'node',
    include: ['tests/unit/**/*.test.ts'],
    coverage: {
      provider: 'v8',
      reporter: ['text', 'json', 'html'],
    },
    setupFiles: ['./tests/setup.ts'],
  },
});

tests/setup.ts

typescript

import 'dotenv/config';
import { beforeAll, afterAll, vi } from 'vitest';

beforeAll(() => {
  // Global setup
});

afterAll(() => {
  vi.restoreAllMocks();
});

tests/unit/mistral.test.ts

typescript

import { describe, it, expect, vi, beforeEach } from 'vitest';
import { getMistralClient } from '../../src/mistral/client';

// Mock the Mistral SDK
vi.mock('@mistralai/mistralai', () => ({
  default: vi.fn().mockImplementation(() => ({
    chat: {
      complete: vi.fn().mockResolvedValue({
        choices: [{ message: { content: 'Mocked response' } }],
      }),
    },
    models: {
      list: vi.fn().mockResolvedValue({ data: [] }),
    },
  })),
}));

describe('Mistral Client', () => {
  beforeEach(() => {
    vi.clearAllMocks();
  });

  it('should initialize with API key', () => {
    const client = getMistralClient();
    expect(client).toBeDefined();
  });

  it('should complete chat successfully', async () => {
    const client = getMistralClient();
    const response = await client.chat.complete({
      model: 'mistral-small-latest',
      messages: [{ role: 'user', content: 'Test' }],
    });
    expect(response.choices?.[0]?.message?.content).toBe('Mocked response');
  });
});

Step 5: Create Client Wrapper

src/mistral/client.ts

typescript

import Mistral from '@mistralai/mistralai';
import 'dotenv/config';

let instance: Mistral | null = null;

export function getMistralClient(): Mistral {
  if (!instance) {
    const apiKey = process.env.MISTRAL_API_KEY;
    if (!apiKey) {
      throw new Error('MISTRAL_API_KEY environment variable is required');
    }
    instance = new Mistral({ apiKey });
  }
  return instance;
}

// Reset for testing
export function resetClient(): void {
  instance = null;
}

Output

Working development environment with hot reload
Configured test suite with mocking
Environment variable management
Fast iteration cycle for Mistral development

Error Handling

Error	Cause	Solution
Module not found	Missing dependency	Run `npm install`
Env not loaded	Missing .env.local	Copy from .env.example
Test timeout	Slow network	Increase test timeout
Type errors	Missing types	Check @types packages

Examples

Mock Mistral Responses in Tests

typescript

import { vi } from 'vitest';

vi.mock('@mistralai/mistralai', () => ({
  default: vi.fn().mockImplementation(() => ({
    chat: {
      complete: vi.fn().mockResolvedValue({
        id: 'test-id',
        object: 'chat.completion',
        model: 'mistral-small-latest',
        choices: [{
          index: 0,
          message: { role: 'assistant', content: 'Mocked!' },
          finishReason: 'stop',
        }],
        usage: { promptTokens: 10, completionTokens: 5, totalTokens: 15 },
      }),
      stream: vi.fn().mockImplementation(async function* () {
        yield { data: { choices: [{ delta: { content: 'Streaming ' } }] } };
        yield { data: { choices: [{ delta: { content: 'response' } }] } };
      }),
    },
  })),
}));

Debug Mode

bash

# Enable verbose logging
DEBUG=mistral:* npm run dev

# Or in code
const client = new Mistral({
  apiKey: process.env.MISTRAL_API_KEY,
  // Enable debug logging
});

Resources

Next Steps

See mistral-sdk-patterns for production-ready code patterns.

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mistral-local-dev-loop

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SKILL.md

Mistral AI Local Dev Loop

Overview

Prerequisites

Instructions

Step 1: Create Project Structure

Step 2: Configure Environment

Step 3: Setup Hot Reload

Step 4: Configure Testing

Step 5: Create Client Wrapper

Output

Error Handling

Examples

Mock Mistral Responses in Tests

Debug Mode

Resources

Next Steps