feat(core): Add enableTruncation option to OpenAI integration (#20167)

This PR adds an `enableTruncation` option to the OpenAI integration that
allows users to disable input message truncation. It defaults to `true`
to preserve existing behavior.

Closes: #20135

Author: andreiborza

dev-packages/node-integration-tests/suites/tracing/openai/instrument-no-truncation.mjs

@@ -0,0 +1,23 @@
+import * as Sentry from '@sentry/node';
+import { loggingTransport } from '@sentry-internal/node-integration-tests';
+
+Sentry.init({
+  dsn: 'https://public@dsn.ingest.sentry.io/1337',
+  release: '1.0',
+  tracesSampleRate: 1.0,
+  sendDefaultPii: false,
+  transport: loggingTransport,
+  integrations: [
+    Sentry.openAIIntegration({
+      recordInputs: true,
+      recordOutputs: true,
+      enableTruncation: false,
+    }),
+  ],
+  beforeSendTransaction: event => {
+    if (event.transaction.includes('/openai/')) {
+      return null;
+    }
+    return event;
+  },
+});

dev-packages/node-integration-tests/suites/tracing/openai/scenario-no-truncation.mjs

@@ -0,0 +1,81 @@
+import * as Sentry from '@sentry/node';
+import express from 'express';
+import OpenAI from 'openai';
+
+function startMockServer() {
+  const app = express();
+  app.use(express.json({ limit: '10mb' }));
+
+  app.post('/openai/chat/completions', (req, res) => {
+    res.send({
+      id: 'chatcmpl-mock123',
+      object: 'chat.completion',
+      created: 1677652288,
+      model: req.body.model,
+      choices: [
+        {
+          index: 0,
+          message: { role: 'assistant', content: 'Hello!' },
+          finish_reason: 'stop',
+        },
+      ],
+      usage: { prompt_tokens: 10, completion_tokens: 5, total_tokens: 15 },
+    });
+  });
+
+  app.post('/openai/responses', (req, res) => {
+    res.send({
+      id: 'resp_mock456',
+      object: 'response',
+      created_at: 1677652290,
+      model: req.body.model,
+      output: [
+        {
+          type: 'message',
+          id: 'msg_mock_output_1',
+          status: 'completed',
+          role: 'assistant',
+          content: [{ type: 'output_text', text: 'Response text', annotations: [] }],
+        },
+      ],
+      output_text: 'Response text',
+      status: 'completed',
+      usage: { input_tokens: 5, output_tokens: 3, total_tokens: 8 },
+    });
+  });
+
+  return new Promise(resolve => {
+    const server = app.listen(0, () => {
+      resolve(server);
+    });
+  });
+}
+
+async function run() {
+  const server = await startMockServer();
+
+  await Sentry.startSpan({ op: 'function', name: 'main' }, async () => {
+    const client = new OpenAI({
+      baseURL: `http://localhost:${server.address().port}/openai`,
+      apiKey: 'mock-api-key',
+    });
+
+    // Chat completion with long content (would normally be truncated)
+    const longContent = 'A'.repeat(50_000);
+    await client.chat.completions.create({
+      model: 'gpt-4',
+      messages: [{ role: 'user', content: longContent }],
+    });
+
+    // Responses API with long string input (would normally be truncated)
+    const longStringInput = 'B'.repeat(50_000);
+    await client.responses.create({
+      model: 'gpt-4',
+      input: longStringInput,
+    });
+  });
+
+  server.close();
+}
+
+run();

dev-packages/node-integration-tests/suites/tracing/openai/test.ts

@@ -345,6 +345,43 @@ describe('OpenAI integration', () => {
     });
   });
 
+  const longContent = 'A'.repeat(50_000);
+
+  const EXPECTED_TRANSACTION_NO_TRUNCATION = {
+    transaction: 'main',
+    spans: expect.arrayContaining([
+      // Chat completion with long content should not be truncated
+      expect.objectContaining({
+        data: expect.objectContaining({
+          [GEN_AI_INPUT_MESSAGES_ATTRIBUTE]: JSON.stringify([{ role: 'user', content: longContent }]),
+          [GEN_AI_INPUT_MESSAGES_ORIGINAL_LENGTH_ATTRIBUTE]: 1,
+        }),
+      }),
+      // Responses API long string input should not be truncated or wrapped in quotes
+      expect.objectContaining({
+        data: expect.objectContaining({
+          [GEN_AI_INPUT_MESSAGES_ATTRIBUTE]: 'B'.repeat(50_000),
+          [GEN_AI_INPUT_MESSAGES_ORIGINAL_LENGTH_ATTRIBUTE]: 1,
+        }),
+      }),
+    ]),
+  };
+
+  createEsmAndCjsTests(
+    __dirname,
+    'scenario-no-truncation.mjs',
+    'instrument-no-truncation.mjs',
+    (createRunner, test) => {
+      test('does not truncate input messages when enableTruncation is false', async () => {
+        await createRunner()
+          .ignore('event')
+          .expect({ transaction: EXPECTED_TRANSACTION_NO_TRUNCATION })
+          .start()
+          .completed();
+      });
+    },
+  );
+
   const EXPECTED_TRANSACTION_DEFAULT_PII_FALSE_EMBEDDINGS = {
     transaction: 'main',
     spans: expect.arrayContaining([

packages/core/src/tracing/ai/utils.ts

@@ -169,6 +169,17 @@ export function endStreamSpan(span: Span, state: StreamResponseState, recordOutp
   span.end();
 }
 
+/**
+ * Serialize a value to a JSON string without truncation.
+ * Strings are returned as-is, arrays and objects are JSON-stringified.
+ */
+export function getJsonString<T>(value: T | T[]): string {
+  if (typeof value === 'string') {
+    return value;
+  }
+  return JSON.stringify(value);
+}
+
 /**
  * Get the truncated JSON string for a string or array of strings.
  *

packages/core/src/tracing/openai/index.ts

@@ -19,6 +19,7 @@ import type { InstrumentedMethodEntry } from '../ai/utils';
 import {
   buildMethodPath,
   extractSystemInstructions,
+  getJsonString,
   getTruncatedJsonString,
   resolveAIRecordingOptions,
   wrapPromiseWithMethods,
@@ -78,7 +79,12 @@ function extractRequestAttributes(args: unknown[], operationName: string): Recor
 }
 
 // Extract and record AI request inputs, if present. This is intentionally separate from response attributes.
-function addRequestAttributes(span: Span, params: Record<string, unknown>, operationName: string): void {
+function addRequestAttributes(
+  span: Span,
+  params: Record<string, unknown>,
+  operationName: string,
+  enableTruncation: boolean,
+): void {
   // Store embeddings input on a separate attribute and do not truncate it
   if (operationName === 'embeddings' && 'input' in params) {
     const input = params.input;
@@ -119,8 +125,10 @@ function addRequestAttributes(span: Span, params: Record<string, unknown>, opera
     span.setAttribute(GEN_AI_SYSTEM_INSTRUCTIONS_ATTRIBUTE, systemInstructions);
   }
 
-  const truncatedInput = getTruncatedJsonString(filteredMessages);
-  span.setAttribute(GEN_AI_INPUT_MESSAGES_ATTRIBUTE, truncatedInput);
+  span.setAttribute(
+    GEN_AI_INPUT_MESSAGES_ATTRIBUTE,
+    enableTruncation ? getTruncatedJsonString(filteredMessages) : getJsonString(filteredMessages),
+  );
 
   if (Array.isArray(filteredMessages)) {
     span.setAttribute(GEN_AI_INPUT_MESSAGES_ORIGINAL_LENGTH_ATTRIBUTE, filteredMessages.length);
@@ -162,7 +170,7 @@ function instrumentMethod<T extends unknown[], R>(
         originalResult = originalMethod.apply(context, args);
 
         if (options.recordInputs && params) {
-          addRequestAttributes(span, params, operationName);
+          addRequestAttributes(span, params, operationName, options.enableTruncation ?? true);
         }
 
         // Return async processing
@@ -200,7 +208,7 @@ function instrumentMethod<T extends unknown[], R>(
       originalResult = originalMethod.apply(context, args);
 
       if (options.recordInputs && params) {
-        addRequestAttributes(span, params, operationName);
+        addRequestAttributes(span, params, operationName, options.enableTruncation ?? true);
       }
 
       return originalResult.then(

packages/core/src/tracing/openai/types.ts

@@ -22,6 +22,11 @@ export interface OpenAiOptions {
    * Enable or disable output recording.
    */
   recordOutputs?: boolean;
+  /**
+   * Enable or disable truncation of recorded input messages.
+   * Defaults to `true`.
+   */
+  enableTruncation?: boolean;
 }
 
 export interface OpenAiClient {