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Reference

Here is the main structure of the promptfoo configuration file:

Config​

PropertyTypeRequiredDescription
descriptionstringNoOptional description of what your LLM is trying to do
tagsRecord<string, string>NoOptional tags to describe the test suite (e.g. env: production, application: chatbot)
providersstring | string[] | Record<string, ProviderOptions> | ProviderOptions[]YesOne or more LLM APIs to use
promptsstring | string[]YesOne or more prompts to load
testsstring | Test Case[]YesPath to a test file, OR list of LLM prompt variations (aka "test case")
defaultTestPartial Test CaseNoSets the default properties for each test case. Useful for setting an assertion, on all test cases, for example.
outputPathstringNoWhere to write output. Writes to console/web viewer if not set.
evaluateOptions.maxConcurrencynumberNoMaximum number of concurrent requests. Defaults to 4
evaluateOptions.repeatnumberNoNumber of times to run each test case . Defaults to 1
evaluateOptions.delaynumberNoForce the test runner to wait after each API call (milliseconds)
evaluateOptions.showProgressBarbooleanNoWhether to display the progress bar
extensionsstring[]NoList of extension files to load. Each extension is a file path with a function name. Can be Python (.py) or JavaScript (.js) files. Supported hooks are 'beforeAll', 'afterAll', 'beforeEach', 'afterEach'.

Test Case​

A test case represents a single example input that is fed into all prompts and providers.

PropertyTypeRequiredDescription
descriptionstringNoDescription of what you're testing
varsRecord<string, string | string[] | any> | stringNoKey-value pairs to substitute in the prompt. If vars is a plain string, it will be treated as a YAML filepath to load a var mapping from.
providerstring | ProviderOptions | ApiProviderNoOverride the default provider for this specific test case
assertAssertion[]NoList of automatic checks to run on the LLM output
thresholdnumberNoTest will fail if the combined score of assertions is less than this number
metadataRecord<string, string | string[] | any>NoAdditional metadata to include with the test case, useful for filtering or grouping results
optionsObjectNoAdditional configuration settings for the test case
options.transformVarsstringNoA filepath (js or py) or JavaScript snippet that runs on the vars before they are substituted into the prompt
options.transformstringNoA filepath (js or py) or JavaScript snippet that runs on LLM output before any assertions
options.prefixstringNoText to prepend to the prompt
options.suffixstringNoText to append to the prompt
options.providerstringNoThe API provider to use for LLM rubric grading
options.runSeriallybooleanNoIf true, run this test case without concurrency regardless of global settings
options.storeOutputAsstringNoThe output of this test will be stored as a variable, which can be used in subsequent tests
options.rubricPromptstring | string[]NoModel-graded LLM prompt

Assertion​

More details on using assertions, including examples here.

PropertyTypeRequiredDescription
typestringYesType of assertion
valuestringNoThe expected value, if applicable
thresholdnumberNoThe threshold value, applicable only to certain types such as similar, cost, javascript, python
providerstringNoSome assertions (type = similar, llm-rubric, model-graded-*) require an LLM provider
metricstringNoThe label for this result. Assertions with the same metric will be aggregated together
note

promptfoo supports .js and .json file extensions in addition to .yaml.

It automatically loads promptfooconfig.*, but you can use a custom config file with promptfoo eval -c path/to/config.

Extension Hooks​

promptfoo supports extension hooks that allow you to run custom code at specific points in the evaluation lifecycle. These hooks are defined in extension files specified in the extensions property of the configuration.

Available Hooks​

Hook NameDescriptionArguments
beforeAllRuns before the entire test suite begins{ suite: TestSuite }
afterAllRuns after the entire test suite has finished{ results: EvaluateResult[], suite: TestSuite }
beforeEachRuns before each individual test{ test: TestCase }
afterEachRuns after each individual test{ test: TestCase, result: EvaluateResult }

Implementing Hooks​

To implement these hooks, create a JavaScript or Python file with a function that handles the hooks you want to use. Then, specify the path to this file and the function name in the extensions array in your configuration.

note

All extensions receive all event types (beforeAll, afterAll, beforeEach, afterEach). It's up to the extension function to decide which events to handle based on the hookName parameter.

Example configuration:

extensions:
  - file://path/to/your/extension.js:extensionHook
  - file://path/to/your/extension.py:extension_hook
important

When specifying an extension in the configuration, you must include the function name after the file path, separated by a colon (:). This tells promptfoo which function to call in the extension file.

Example extension file (Python):

def extension_hook(hook_name, context):
    if hook_name == 'beforeAll':
        print(f"Setting up test suite: {context['suite'].get('description', '')}")
        # Perform any necessary setup
    elif hook_name == 'afterAll':
        print(f"Test suite completed: {context['suite'].get('description', '')}")
        print(f"Total tests: {len(context['results'])}")
        # Perform any necessary teardown or reporting
    elif hook_name == 'beforeEach':
        print(f"Running test: {context['test'].get('description', '')}")
        # Prepare for individual test
    elif hook_name == 'afterEach':
        print(f"Test completed: {context['test'].get('description', '')}. Pass: {context['result'].get('success', False)}")
        # Clean up after individual test or log results

Example extension file (JavaScript):

async function extensionHook(hookName, context) {
  if (hookName === 'beforeAll') {
    console.log(`Setting up test suite: ${context.suite.description || ''}`);
    // Perform any necessary setup
  } else if (hookName === 'afterAll') {
    console.log(`Test suite completed: ${context.suite.description || ''}`);
    console.log(`Total tests: ${context.results.length}`);
    // Perform any necessary teardown or reporting
  } else if (hookName === 'beforeEach') {
    console.log(`Running test: ${context.test.description || ''}`);
    // Prepare for individual test
  } else if (hookName === 'afterEach') {
    console.log(
      `Test completed: ${context.test.description || ''}. Pass: ${context.result.success || false}`,
    );
    // Clean up after individual test or log results
  }
}

module.exports = extensionHook;

These hooks provide powerful extensibility to your promptfoo evaluations, allowing you to implement custom logic for setup, teardown, logging, or integration with other systems. The extension function receives the hookName and a context object, which contains relevant data for each hook type. You can use this information to perform actions specific to each stage of the evaluation process.

ProviderFunction​

A ProviderFunction is a function that takes a prompt as an argument and returns a Promise that resolves to a ProviderResponse. It allows you to define custom logic for calling an API.

type ProviderFunction = (
  prompt: string,
  context: { vars: Record<string, string | object> },
) => Promise<ProviderResponse>;

ProviderOptions​

ProviderOptions is an object that includes the id of the provider and an optional config object that can be used to pass provider-specific configurations.

interface ProviderOptions {
  id?: ProviderId;
  config?: any;

  // List of prompt display strings
  prompts?: string[];

  // Transform the output, either with inline Javascript or external py/js script (see `Transforms`)
  transform?: string;

  // Sleep this long before each request
  delay?: number;
}

ProviderResponse​

ProviderResponse is an object that represents the response from a provider. It includes the output from the provider, any error that occurred, information about token usage, and a flag indicating whether the response was cached.

interface ProviderResponse {
  error?: string;
  output?: string | object;
  tokenUsage?: Partial<{
    total: number;
    prompt: number;
    completion: number;
    cached?: number;
  }>;
  cached?: boolean;
  cost?: number; // required for cost assertion
  logProbs?: number[]; // required for perplexity assertion
}

ProviderEmbeddingResponse​

ProviderEmbeddingResponse is an object that represents the response from a provider's embedding API. It includes the embedding from the provider, any error that occurred, and information about token usage.

interface ProviderEmbeddingResponse {
  error?: string;
  embedding?: number[];
  tokenUsage?: Partial<TokenUsage>;
}

Evaluation inputs​

TestSuiteConfiguration​

interface TestSuiteConfig {
  // Optional description of what you're trying to test
  description?: string;

  // One or more LLM APIs to use, for example: openai:gpt-4o-mini, openai:gpt-4o, localai:chat:vicuna
  providers: ProviderId | ProviderFunction | (ProviderId | ProviderOptionsMap | ProviderOptions)[];

  // One or more prompts
  prompts: (FilePath | Prompt | PromptFunction)[];

  // Path to a test file, OR list of LLM prompt variations (aka "test case")
  tests: FilePath | (FilePath | TestCase)[];

  // Scenarios, groupings of data and tests to be evaluated
  scenarios?: Scenario[];

  // Sets the default properties for each test case. Useful for setting an assertion, on all test cases, for example.
  defaultTest?: Omit<TestCase, 'description'>;

  // Path to write output. Writes to console/web viewer if not set.
  outputPath?: FilePath | FilePath[];

  // Determines whether or not sharing is enabled.
  sharing?:
    | boolean
    | {
        apiBaseUrl?: string;
        appBaseUrl?: string;
      };

  // Nunjucks filters
  nunjucksFilters?: Record<string, FilePath>;

  // Envar overrides
  env?: EnvOverrides;

  // Whether to write latest results to promptfoo storage. This enables you to use the web viewer.
  writeLatestResults?: boolean;
}

UnifiedConfig​

UnifiedConfig is an object that includes the test suite configuration, evaluation options, and command line options. It is used to hold the complete configuration for the evaluation.

interface UnifiedConfig extends TestSuiteConfiguration {
  evaluateOptions: EvaluateOptions;
  commandLineOptions: Partial<CommandLineOptions>;
}

Scenario​

Scenario is an object that represents a group of test cases to be evaluated. It includes a description, default test case configuration, and a list of test cases.

interface Scenario {
  description?: string;
  config: Partial<TestCase>[];
  tests: TestCase[];
}

Also, see this table here for descriptions.

Prompt​

A Prompt is what it sounds like. When specifying a prompt object in a static config, it should look like this:

interface Prompt {
  id: string; // Path, usually prefixed with file://
  label: string; // How to display it in outputs and web UI
}

When passing a Prompt object directly to the Javascript library:

interface Prompt {
  // The actual prompt
  raw: string;
  // How it should appear in the UI
  label: string;
  // A function to generate a prompt on a per-input basis. Overrides the raw prompt.
  function?: (context: {
    vars: Record<string, string | object>;
    provider?: ApiProvider;
  }) => Promise<string | object>;
}

EvaluateOptions​

EvaluateOptions is an object that includes options for how the evaluation should be performed. It includes the maximum concurrency for API calls, whether to show a progress bar, a callback for progress updates, the number of times to repeat each test, and a delay between tests.

interface EvaluateOptions {
  maxConcurrency?: number;
  showProgressBar?: boolean;
  progressCallback?: (progress: number, total: number) => void;
  generateSuggestions?: boolean;
  repeat?: number;
  delay?: number;
}

Evaluation outputs​

EvaluateTable​

EvaluateTable is an object that represents the results of the evaluation in a tabular format. It includes a header with the prompts and variables, and a body with the outputs and variables for each test case.

interface EvaluateTable {
  head: {
    prompts: Prompt[];
    vars: string[];
  };
  body: {
    outputs: EvaluateTableOutput[];
    vars: string[];
  }[];
}

EvaluateTableOutput​

EvaluateTableOutput is an object that represents the output of a single evaluation in a tabular format. It includes the pass/fail result, score, output text, prompt, latency, token usage, and grading result.

interface EvaluateTableOutput {
  pass: boolean;
  score: number;
  text: string;
  prompt: string;
  latencyMs: number;
  tokenUsage?: Partial<TokenUsage>;
  gradingResult?: GradingResult;
}

EvaluateSummary​

EvaluateSummary is an object that represents a summary of the evaluation results. It includes the version of the evaluator, the results of each evaluation, a table of the results, and statistics about the evaluation. The latest version is 3. It removed the table and added in a new prompts property.

interface EvaluateSummaryV3 {
  version: 3;
  timestamp: string; // ISO 8601 datetime
  results: EvaluateResult[];
  prompts: CompletedPrompt[];
  stats: EvaluateStats;
}
interface EvaluateSummaryV2 {
  version: 2;
  timestamp: string; // ISO 8601 datetime
  results: EvaluateResult[];
  table: EvaluateTable;
  stats: EvaluateStats;
}

EvaluateStats​

EvaluateStats is an object that includes statistics about the evaluation. It includes the number of successful and failed tests, and the total token usage.

interface EvaluateStats {
  successes: number;
  failures: number;
  tokenUsage: Required<TokenUsage>;
}

EvaluateResult​

EvaluateResult roughly corresponds to a single "cell" in the grid comparison view. It includes information on the provider, prompt, and other inputs, as well as the outputs.

interface EvaluateResult {
  provider: Pick<ProviderOptions, 'id'>;
  prompt: Prompt;
  vars: Record<string, string | object>;
  response?: ProviderResponse;
  error?: string;
  success: boolean;
  score: number;
  latencyMs: number;
  gradingResult?: GradingResult;
}

GradingResult​

GradingResult is an object that represents the result of grading a test case. It includes whether the test case passed, the score, the reason for the result, the tokens used, and the results of any component assertions.

interface GradingResult {
  pass: boolean;                        # did test pass?
  score: number;                        # score between 0 and 1
  reason: string;                       # plaintext reason for outcome
  tokensUsed?: TokenUsage;              # tokens consumed by the test
  componentResults?: GradingResult[];   # if this is a composite score, it can have nested results
  assertion: Assertion | null;          # source of assertion
  latencyMs?: number;                   # latency of LLM call
}

CompletedPrompt​

CompletedPrompt is an object that represents a prompt that has been evaluated. It includes the raw prompt, the provider, metrics, and other information.

interface CompletedPrompt {
  id?: string;
  raw: string;
  label: string;
  function?: PromptFunction;

  // These config options are merged into the provider config.
  config?: any;
  provider: string;
  metrics?: {
    score: number;
    testPassCount: number;
    testFailCount: number;
    assertPassCount: number;
    assertFailCount: number;
    totalLatencyMs: number;
    tokenUsage: TokenUsage;
    namedScores: Record<string, number>;
    namedScoresCount: Record<string, number>;
    redteam?: {
      pluginPassCount: Record<string, number>;
      pluginFailCount: Record<string, number>;
      strategyPassCount: Record<string, number>;
      strategyFailCount: Record<string, number>;
    };
    cost: number;
  };
}