promptfoo--promptfoo/docs/agents/logging.md

Logging Guidelines

The Rule

Always use the logger with an object as the second parameter:

logger.debug('[Component] Message', { headers, body, config });

The object is auto-sanitized - sensitive fields are automatically redacted.

Why This Matters

• Security: Prevents accidental exposure of secrets in logs
• Consistency: Structured logs are easier to search and analyze
• Safety: Red team test content may contain harmful/sensitive data

Correct Usage

import logger from './logger';

// Good - context object is auto-sanitized
logger.debug('[Provider]: Making API request', {
  url: 'https://api.example.com',
  method: 'POST',
  headers: { Authorization: 'Bearer secret-token' },
  body: { apiKey: 'secret-key', data: 'value' },
});
// Output: Authorization and apiKey are [REDACTED]

logger.error('Request failed', {
  headers: response.headers,
  body: errorResponse,
});

Anti-Pattern

// WRONG - exposes secrets, bypasses sanitization
logger.debug(`Config: ${JSON.stringify(config)}`);
logger.debug(`Calling ${url} with headers: ${JSON.stringify(headers)}`);

Manual Sanitization

For non-logging contexts:

import { sanitizeObject } from './util/sanitizer';

const sanitizedConfig = sanitizeObject(providerConfig, {
  context: 'provider config',
});

What Gets Sanitized

Field names containing (case-insensitive, works with -, _, camelCase):

Category	Fields
Passwords	password, passwd, pwd, passphrase
API Keys	apiKey, api_key, token, accessToken, refreshToken, bearerToken
Secrets	secret, clientSecret, webhookSecret
Headers	authorization, cookie, x-api-key, x-auth-token
Certificates	privateKey, certificatePassword, keystorePassword
Signatures	signature, sig, signingKey

See src/util/sanitizer.ts for the complete list.