Tracing allows you to monitor and analyze complex workflows in your AI applications. Unlike basic monitoring, tracing provides a comprehensive framework for tracking multi-step processes, nested operations, and complex interactions across your entire application.
While basic monitoring is designed for simple prompt-to-response interactions, tracing is ideal for complex workflows involving multiple steps, parallel processes, and branching logic. Tracing gives you deeper visibility into your AI application’s behavior and performance.

​
Create a Trace

A trace represents a complete user interaction or process flow and serves as the top-level container for all monitoring activities. To create a trace, you’ll use the createTrace method: 
const trace = basalt.monitor.createTrace('feature-slug', {
  name: 'Human-readable name', // Optional, defaults to feature-slug
  input: 'Initial input',      // Optional
  metadata: {                  // Optional
    userId: 'user123',
    contentType: 'article'
  }
})
The feature-slug is a unique identifier that helps you categorize and group related traces in your analytics dashboard. The trace becomes the parent container for all logs and generations in your workflow.
It’s essential to call the end() method on your trace when the workflow is complete. Without calling end(), the trace data will not be sent to Basalt for analysis. This applies even if an error occurs in your workflow.

​
User and Organization Identification

You can associate a trace with specific users and organizations to enable more powerful analytics, filtering, and user-specific insights: 
// When creating the trace
const trace = basalt.monitor.createTrace('feature-slug', {
  user: {
    id: 'user123',
    name: 'John Doe',
    email: 'john@example.com' // Optional
  },
  organization: {
    id: 'org456',
    name: 'Acme Inc.'
  }
})

// Or later using the identify method
trace.identify({
  user: {
    id: 'user123',
    name: 'John Doe'
  },
  organization: {
    id: 'org456',
    name: 'Acme Inc.'
  }
})
The identify method allows you to add or update user and organization information at any point during the trace’s lifecycle. This is particularly useful when user details become available partway through a workflow.

​
Adding Metadata

Metadata provides additional context that helps you understand what happened during your workflow. You can add metadata when creating components or update it later: 
// Initial metadata when creating the trace
const trace = basalt.monitor.createTrace('feature-slug', {
  metadata: {
    source: 'web-app',
    region: 'us-west',
    priority: 'high'
  }
})

// Update or add metadata using setMetadata
trace.setMetadata({
  processingTime: 1250, // ms
  tokenCount: 1024,
  modelVersion: 'gpt-4o'
})

// Alternatively, use the update method
trace.update({
  metadata: {
    status: 'completed',
    successRate: 0.95
  }
})
Metadata is flexible and can include any JSON-serializable data. Good metadata makes debugging, analysis, and optimization much easier, so consider adding relevant context at each step of your workflow.

​
Create Logs (Spans)

Logs represent discrete operations or steps within your workflow. In tracing terminology, these are often called “spans”, and Basalt supports several specific types of logs for different purposes.

​
Available Log Types

The type parameter defines the nature of the operation being logged:
  • span: A general-purpose operation or step in your workflow
  • function: A specific function call or computation
  • tool: External tool usage (like a database query or API call)
  • retrieval: Data retrieval operations (like RAG or knowledge base lookups)
  • event: Notable events or state changes in your application

​
Basic Log Creation

// Create a log within a trace
const log = trace.createLog({
  name: 'data-processing',
  type: 'span',             // One of the available types
  input: 'Raw input data',  // Optional
  metadata: {               // Optional
    processingType: 'text-analysis',
    priority: 'medium'
  }
})

​
Log Lifecycle Methods

Logs have methods to track their lifecycle: 
// Start the log (automatically called if not explicitly started)
log.start()

// Add or update metadata
log.setMetadata({
  status: 'processing',
  progress: 50
})

// End the log with optional output
log.end('Processed output data')

​
Creating Nested Logs

You can create hierarchical structures by nesting logs: 
// Create a nested log within another log
const nestedLog = parentLog.createLog({
  name: 'validation-step',
  type: 'function'
})

​
Create Generations

Generations represent AI model completions within your workflow. The Basalt SDK provides several ways to create and manage generations.

​
Basic Generation Creation

// Create a generation within a trace or log
const generation = trace.createGeneration({
  name: 'text-completion',
  input: 'Generate an article about AI monitoring'
})

​
Prompt Parameters

When using Basalt-managed prompts, you can reference them directly: 
const generation = trace.createGeneration({
  name: 'text-completion',
  prompt: {                     // Reference to a Basalt-managed prompt
    slug: 'article-generator',  // Required
    version: '1.2.0',           // Optional
    tag: 'production'           // Optional
  },
  input: 'Generate an article about AI monitoring'
})

​
Variables and Metadata

You can include variables for prompt templates and additional metadata: 
const generation = trace.createGeneration({
  name: 'text-completion',
  prompt: {
    slug: 'article-generator'
  },
  input: 'Generate an article about AI monitoring',
  variables: {                  // Variables for prompt templates
    topic: 'AI monitoring',
    tone: 'informative',
    length: 'medium'
  },
  metadata: {                   // Additional context
    modelName: 'gpt-4o',
    temperature: 0.7,
    priority: 'high'
  }
})
In Python, the variables are converted to a standardized format internally, but you can provide them as a simple dictionary as shown above.

​
Ending Generations

There are multiple ways to end a generation depending on what information you have available: 
// Basic ending with just the output text
generation.end('The generated text response from the LLM')

// Ending with detailed metrics
generation.end({
  output: 'The generated text response from the LLM',
  inputTokens: 150,    // Optional: number of tokens in the input
  outputTokens: 450,   // Optional: number of tokens in the output 
  cost: 0.0125         // Optional: cost of the generation in USD
})
If you don’t provide token counts or cost information, Basalt will attempt to calculate these values automatically based on the input and output text. However, providing these values directly is more accurate, especially if you have this information from your LLM provider.

​
Nesting Logs and Generations

Basalt’s tracing system allows you to create hierarchical structures that accurately represent the flow of your application.

​
Creating Nested Structures

// Create a parent log
const parentLog = trace.createLog({
  name: 'data-processing',
  type: 'span'
})

// Create a nested log within the parent log
const nestedLog = parentLog.createLog({
  name: 'validation',
  type: 'function'
})

// Create a generation within the nested log
const generation = nestedLog.createGeneration({
  name: 'validation-check',
  input: 'Validate this data structure'
})

​
Appending Existing Generations

You can append existing generations (such as those from prompt.get()) to logs or traces: 
// Get a prompt from Basalt, which returns a generation object
const { value, error, generation } = await basalt.prompt.get('article-generator', {
  variables: {
    topic: 'AI monitoring'
  }
})

// Append this generation to a log
myLog.append(generation)

// or directly to the trace
trace.append(generation)
The append method is particularly useful when integrating Basalt-managed prompts into your tracing workflow. When you append a generation to a log or trace, the generation is properly associated with its new parent, maintaining the hierarchical structure of your workflow.

​
Using Evaluators

Evaluators automatically assess the quality of your generations based on predefined criteria. This provides objective metrics about your AI outputs. 
// Add evaluators when creating a trace
const trace = basalt.monitor.createTrace('content-processing', {
  evaluators: [
    { slug: 'hallucination' },
    { slug: 'toxicity' }
  ],
  evaluationConfig: {
    sampleRate: 0.1  // Run evaluations on 10% of traces
  }
})

// Add evaluators to a specific generation
const generation = trace.createGeneration({
  name: 'content-generation',
  evaluators: [
    { slug: 'sentiment-analysis' }
  ]
})

// Add evaluators later
generation.addEvaluator({ slug: 'factual-consistency' })
Evaluators run automatically when the trace or generation ends. The sampleRate parameter controls how often evaluations are run, which can help manage costs for large-scale applications. For more information on available evaluators and how to create custom ones, see the Evaluation documentation.

​
Complete Example

Here’s a complete example of using tracing to monitor a content processing workflow: 
async function processUserContent(user, content) {
  // Create the main trace for the entire content processing workflow
  const mainTrace = basalt.monitor.createTrace('content-workflow', {
    name: 'Content Processing Workflow',
    input: content,
    user: {
      id: user.id,
      name: user.name,
      email: user.email
    },
    organization: {
      id: user.organizationId,
      name: user.organizationName
    },
    metadata: {
      contentType: 'article',
      contentLength: content.length,
      requestTimestamp: new Date().toISOString()
    }
  })
  
  try {
    // Step 1: Content Analysis
    const analysisLog = mainTrace.createLog({
      name: 'content-analysis',
      type: 'span',
      input: content
    })
    
    // Get a prompt from Basalt for topic extraction
    const { value: topicPrompt, error: promptError, generation: topicGeneration } = 
      await basalt.prompt.get('topic-extractor', {
        variables: {
          content: content
        }
      })
    
    if (promptError) {
      throw promptError
    }
    
    // Append the generation to our analysis log
    analysisLog.append(topicGeneration)
    
    // Call your LLM provider
    const topics = await yourLLMProvider.complete(topicPrompt.text)
    
    // Record the generation result
    topicGeneration.end(topics)
    
    // Update analysis log with results
    analysisLog.update({
      metadata: {
        topicsIdentified: topics.split(',').length,
        mainTopic: topics.split(',')[0]
      }
    })
    
    analysisLog.end(`Identified topics: ${topics}`)
    
    // Step 2: Run enhancement and translation in parallel
    const parallelLog = mainTrace.createLog({
      name: 'parallel-processing',
      type: 'span',
      input: content,
      metadata: {
        operations: ['enhancement', 'translation']
      }
    })
    
    // Create two tasks that will run in parallel
    const enhancementPromise = enhanceContent(content, parallelLog)
    const translationPromise = translateContent(content, parallelLog)
    
    // Wait for both operations to complete
    const [enhancedContent, translatedContent] = await Promise.all([
      enhancementPromise, 
      translationPromise
    ])
    
    parallelLog.end()
    
    // Step 3: Summarization
    const summaryGeneration = mainTrace.createGeneration({
      name: 'content-summarization',
      prompt: {
        slug: 'summarizer'
      },
      input: enhancedContent,
      variables: {
        length: 'short',
        style: 'professional'
      },
      metadata: {
        originalContentLength: content.length,
        enhancedContentLength: enhancedContent.length
      }
    })
    
    // Generate the summary
    const summary = await yourLLMProvider.complete({
      prompt: `Summarize the following content: ${enhancedContent}`,
      model: 'gpt-4o'
    })
    
    // Record the summary with token counts and cost
    summaryGeneration.end({
      output: summary,
      inputTokens: calculateTokens(enhancedContent),
      outputTokens: calculateTokens(summary),
      cost: 0.02  // Example cost in USD
    })
    
    // Complete the main trace with final results
    mainTrace.update({
      metadata: {
        processingSteps: 3,
        totalProcessingTime: new Date().getTime() - new Date(mainTrace.startTime).getTime(),
        enhancedContentAvailable: true,
        translationAvailable: true,
        summaryAvailable: true
      }
    })
    
    // End the trace with the final output
    mainTrace.end(summary)
    
    return {
      topics,
      enhancedContent,
      translatedContent,
      summary
    }
  } catch (error) {
    // Record the error
    mainTrace.update({
      metadata: {
        error: {
          name: error.name,
          message: error.message,
          stack: error.stack
        },
        status: 'failed'
      }
    })
    
    // Always end the trace, even in error cases
    mainTrace.end(`Error: ${error.message}`)
    throw error
  }
}

// Helper functions for the content processing
async function enhanceContent(content, parentLog) {
  const enhancementLog = parentLog.createLog({
    name: 'content-enhancement',
    type: 'span',
    input: content
  })
  
  const generation = enhancementLog.createGeneration({
    name: 'enhance-text',
    prompt: {
      slug: 'content-enhancer'
    },
    input: content
  })
  
  // Call your LLM provider
  const enhancedContent = await yourLLMProvider.complete({
    prompt: `Enhance the following content: ${content}`,
    model: 'gpt-4o'
  })
  
  generation.end(enhancedContent)
  enhancementLog.end(enhancedContent)
  
  return enhancedContent
}

async function translateContent(content, parentLog) {
  const translationLog = parentLog.createLog({
    name: 'content-translation',
    type: 'span',
    input: content
  })
  
  const generation = translationLog.createGeneration({
    name: 'translate-text',
    prompt: {
      slug: 'translator'
    },
    input: content,
    variables: {
      targetLanguage: 'Spanish'
    }
  })
  
  // Call your LLM provider
  const translatedContent = await yourLLMProvider.complete({
    prompt: `Translate the following content to Spanish: ${content}`,
    model: 'gpt-4o'
  })
  
  // Let Basalt calculate tokens and cost automatically
  generation.end(translatedContent)
  translationLog.end(translatedContent)
  
  return translatedContent
}
This example demonstrates:
  1. Creating a main trace for the entire workflow
  2. Using specific log types for different operations
  3. Appending generations from prompt.get()
  4. Parallel processing with multiple logs
  5. Different ways to end generations (with and without token/cost data)
  6. Proper error handling and ensuring the trace is always ended
  7. Recording rich metadata at each step

​
Best Practices

For effective tracing:
  1. Always end your traces: Make sure to call end() for all traces, even in error cases, or the data won’t be sent to Basalt.
  2. Choose meaningful names: Use descriptive names that clearly communicate the purpose of each component.
  3. Add relevant metadata: Include information that will help with debugging and analysis later.
  4. Use the right log types: Choose the appropriate type (span, function, tool, etc.) for each operation to improve analytics.
  5. Structure nested components logically: Create a hierarchy that reflects the logical flow of your application.
  6. Handle errors properly: Record errors in your trace metadata and ensure traces are ended even when errors occur.
  7. Consider evaluation needs: Apply evaluators strategically to assess the quality of critical generations.
  8. Optimize sample rates: Adjust evaluation sample rates based on your volume and budget.

​
Advanced Topics

For more advanced tracing capabilities, explore: