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Managing Large Configurations

As your Promptfoo evaluations grow more complex, you'll need strategies to keep your configurations manageable, maintainable, and reusable. This guide covers best practices for organizing large configurations and making them modular.

Separate Configuration Files​

Split your configuration into multiple files based on functionality:

promptfooconfig.yaml
# yaml-language-server: $schema=https://promptfoo.dev/config-schema.json
description: Main evaluation configuration
prompts: file://configs/prompts.yaml
providers: file://configs/providers.yaml
tests: file://configs/tests/
defaultTest: file://configs/default-test.yaml
configs/prompts.yaml
# Prompts configuration
- file://prompts/system-message.txt
- file://prompts/user-prompt.txt
- id: custom-prompt
  label: Custom Prompt
  raw: |
    You are a helpful assistant. Please answer the following question:
    {{question}}
configs/providers.yaml
# Providers configuration
- id: gpt-5.2
  provider: openai:gpt-5.2
  config:
    temperature: 0.7
    max_tokens: 1000
- id: claude-sonnet
  provider: anthropic:claude-sonnet-4-5-20250929
  config:
    temperature: 0.7
    max_tokens: 1000
configs/default-test.yaml
# Default test configuration
assert:
  - type: llm-rubric
    value: Response should be helpful and accurate
  - type: javascript
    value: output.length > 10 && output.length < 500

Test Case Organization​

Organize test cases by domain or functionality:

promptfooconfig.yaml
# yaml-language-server: $schema=https://promptfoo.dev/config-schema.json
description: Multi-domain evaluation
prompts: file://prompts/
providers: file://providers.yaml
tests:
  - file://tests/accuracy/
  - file://tests/safety/
  - file://tests/performance/
  - file://tests/edge-cases/
tests/accuracy/math-problems.yaml
# Math-specific test cases
- description: Basic arithmetic
  vars:
    question: What is 15 + 27?
  assert:
    - type: contains
      value: '42'
    - type: javascript
      value: /4[2]/.test(output)

- description: Word problems
  vars:
    question: If Sarah has 3 apples and gives away 1, how many does she have left?
  assert:
    - type: contains
      value: '2'

Environment-Specific Configurations​

Create environment-specific configurations:

promptfooconfig.yaml
# yaml-language-server: $schema=https://promptfoo.dev/config-schema.json
description: Production evaluation
prompts: file://prompts/
providers: file://configs/providers-prod.yaml
tests: file://tests/
env: file://configs/env-prod.yaml
configs/providers-prod.yaml
# Production providers with rate limiting
- id: gpt-5.2-prod
  provider: openai:gpt-5.2
  config:
    temperature: 0.1
    max_tokens: 500
    requestsPerMinute: 100
- id: claude-sonnet-prod
  provider: anthropic:claude-sonnet-4-5-20250929
  config:
    temperature: 0.1
    max_tokens: 500
    requestsPerMinute: 50
configs/env-prod.yaml
# Production environment variables
OPENAI_API_KEY: '{{ env.OPENAI_API_KEY_PROD }}'
ANTHROPIC_API_KEY: '{{ env.ANTHROPIC_API_KEY_PROD }}'
LOG_LEVEL: info

YAML References and Templates​

Use YAML references to avoid repetition:

promptfooconfig.yaml
# yaml-language-server: $schema=https://promptfoo.dev/config-schema.json
description: Evaluation with reusable components
prompts: file://prompts/
providers: file://providers.yaml

# Define reusable assertion templates
assertionTemplates:
  lengthCheck: &lengthCheck
    type: javascript
    value: output.length > 20 && output.length < 500

  qualityCheck: &qualityCheck
    type: llm-rubric
    value: Response should be clear, helpful, and well-structured

  safetyCheck: &safetyCheck
    type: llm-rubric
    value: Response should not contain harmful or inappropriate content

defaultTest:
  assert:
    - *qualityCheck
    - *safetyCheck

tests:
  - description: Short response test
    vars:
      input: What is AI?
    assert:
      - *lengthCheck
      - *qualityCheck

  - description: Long response test
    vars:
      input: Explain machine learning in detail
    assert:
      - type: javascript
        value: output.length > 100 && output.length < 2000
      - *qualityCheck

Dynamic Configuration with JavaScript​

Use JavaScript configurations for complex logic:

promptfooconfig.js
const baseConfig = {
  description: 'Dynamic configuration example',
  prompts: ['file://prompts/base-prompt.txt'],
  providers: ['openai:gpt-5.2', 'anthropic:claude-sonnet-4-5-20250929'],
};

// Generate test cases programmatically
const categories = ['technology', 'science', 'history', 'literature'];
const difficulties = ['basic', 'intermediate', 'advanced'];

const tests = [];
for (const category of categories) {
  for (const difficulty of difficulties) {
    tests.push({
      vars: {
        category,
        difficulty,
        question: `Generate a ${difficulty} question about ${category}`,
      },
      assert: [
        {
          type: 'contains',
          value: category,
        },
        {
          type: 'javascript',
          value: `
            const wordCount = output.split(' ').length;
            const minWords = ${difficulty === 'basic' ? 5 : difficulty === 'intermediate' ? 15 : 30};
            const maxWords = ${difficulty === 'basic' ? 20 : difficulty === 'intermediate' ? 50 : 100};
            return wordCount >= minWords && wordCount <= maxWords;
          `,
        },
      ],
    });
  }
}

module.exports = {
  ...baseConfig,
  tests,
};

TypeScript Configuration​

Promptfoo configs can be written in TypeScript:

promptfooconfig.ts
import type { UnifiedConfig } from 'promptfoo';

const config: UnifiedConfig = {
  description: 'My evaluation suite',
  prompts: ['Tell me about {{topic}} in {{style}}'],
  providers: ['openai:gpt-5.2', 'anthropic:claude-sonnet-4-5-20250929'],
  tests: [
    {
      vars: {
        topic: 'quantum computing',
        style: 'simple terms',
      },
      assert: [
        {
          type: 'contains',
          value: 'quantum',
        },
      ],
    },
  ],
};

export default config;

Running TypeScript Configs​

Install a TypeScript loader:

npm install tsx

Run with NODE_OPTIONS:

NODE_OPTIONS="--import tsx" promptfoo eval -c promptfooconfig.ts

Dynamic Schema Generation​

Share Zod schemas between your application and promptfoo:

src/schemas/response.ts
import { z } from 'zod';

export const ResponseSchema = z.object({
  answer: z.string(),
  confidence: z.number().min(0).max(1),
  sources: z.array(z.string()).nullable(),
});
promptfooconfig.ts
import { zodResponseFormat } from 'openai/helpers/zod.mjs';
import type { UnifiedConfig } from 'promptfoo';
import { ResponseSchema } from './src/schemas/response';

const responseFormat = zodResponseFormat(ResponseSchema, 'response');

const config: UnifiedConfig = {
  prompts: ['Answer this question: {{question}}'],
  providers: [
    {
      id: 'openai:gpt-5.2',
      config: {
        response_format: responseFormat,
      },
    },
  ],
  tests: [
    {
      vars: { question: 'What is TypeScript?' },
      assert: [{ type: 'is-json' }],
    },
  ],
};

export default config;

See the ts-config example for a complete implementation.

Conditional Configuration Loading​

Create configurations that adapt based on environment:

promptfooconfig.js
const isQuickTest = process.env.TEST_MODE === 'quick';
const isComprehensive = process.env.TEST_MODE === 'comprehensive';

const baseConfig = {
  description: 'Test mode adaptive configuration',
  prompts: ['file://prompts/'],
};

// Quick test configuration
if (isQuickTest) {
  module.exports = {
    ...baseConfig,
    providers: [
      'openai:gpt-5.1-mini', // Faster, cheaper for quick testing
    ],
    tests: 'file://tests/quick/', // Smaller test suite
    env: {
      LOG_LEVEL: 'debug',
    },
  };
}

// Comprehensive test configuration
if (isComprehensive) {
  module.exports = {
    ...baseConfig,
    providers: [
      'openai:gpt-5.2',
      'anthropic:claude-sonnet-4-5-20250929',
      'google:gemini-2.5-flash',
    ],
    tests: 'file://tests/comprehensive/', // Full test suite
    env: {
      LOG_LEVEL: 'info',
    },
    writeLatestResults: true,
  };
}

Directory Structure​

Organize your configuration files in a logical hierarchy:

project/
├── promptfooconfig.yaml              # Main configuration
├── configs/
│   ├── providers/
│   │   ├── development.yaml
│   │   ├── staging.yaml
│   │   └── production.yaml
│   ├── prompts/
│   │   ├── system-prompts.yaml
│   │   ├── user-prompts.yaml
│   │   └── templates.yaml
│   └── defaults/
│       ├── assertions.yaml
│       └── test-config.yaml
├── tests/
│   ├── accuracy/
│   ├── safety/
│   ├── performance/
│   └── edge-cases/
├── prompts/
│   ├── system/
│   ├── user/
│   └── templates/
└── scripts/
    ├── config-generators/
    └── utilities/

See Also​