Selected Text Events

Track selected text events in LangWatch to understand user behavior and improve LLM performance across AI agent evaluations.

Selected text events allow you to track when a user selects text generated by your LLM application, indicating the response was useful enough to be copied and used elsewhere.

REST API Specification

Endpoint

POST /api/track_event

Headers

• X-Auth-Token: Your LangWatch API key.

Request Body

{
  "trace_id": "id of the message the user selected",
  "event_type": "selected_text",
  "metrics": {
    "text_length": 120 // Length of the selected text in characters
  },
  "event_details": {
    "selected_text": "The selected text content"
  },
  "timestamp": 1617981376000, // Unix timestamp in milliseconds
}

Example

curl -X POST "https://app.langwatch.ai/api/track_event" \\
     -H "X-Auth-Token: your_api_key" \\
     -H "Content-Type: application/json" \\
     -d '{
       "trace_id": "trace_Yy0XWu6BOwwnrkLtQh9Ji",
       "event_type": "selected_text",
       "metrics": {
         "text_length": 120
       },
       "event_details": {
         "selected_text": "The capital of France is Paris."
       },
       "timestamp": 1617981376000
     }'

The text_length metric is mandatory and should reflect the length of the selected text. The selected_text field in event_details is optional if you also want to capture the actual text that was selected by the user.