feat(core): Add enableTruncation option to LangGraph integration (#20183)

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

Also refactors to use the shared getTruncatedJsonString/getJsonString
utilities.

Closes: #20139

---------

Co-authored-by: Nicolas Hrubec <nicolas.hrubec@outlook.com>

Author: andreiborza

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

@@ -0,0 +1,17 @@
+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: true,
+  transport: loggingTransport,
+  integrations: [
+    Sentry.langGraphIntegration({
+      recordInputs: true,
+      recordOutputs: true,
+      enableTruncation: false,
+    }),
+  ],
+});

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

@@ -0,0 +1,46 @@
+import { END, MessagesAnnotation, START, StateGraph } from '@langchain/langgraph';
+import * as Sentry from '@sentry/node';
+
+async function run() {
+  await Sentry.startSpan({ op: 'function', name: 'langgraph-test' }, async () => {
+    const mockLlm = () => {
+      return {
+        messages: [
+          {
+            role: 'assistant',
+            content: 'Mock LLM response',
+            response_metadata: {
+              model_name: 'mock-model',
+              finish_reason: 'stop',
+              tokenUsage: {
+                promptTokens: 20,
+                completionTokens: 10,
+                totalTokens: 30,
+              },
+            },
+          },
+        ],
+      };
+    };
+
+    const graph = new StateGraph(MessagesAnnotation)
+      .addNode('agent', mockLlm)
+      .addEdge(START, 'agent')
+      .addEdge('agent', END)
+      .compile({ name: 'weather_assistant' });
+
+    // Multiple messages with long content (would normally be truncated and popped to last message only)
+    const longContent = 'A'.repeat(50_000);
+    await graph.invoke({
+      messages: [
+        { role: 'user', content: longContent },
+        { role: 'assistant', content: 'Some reply' },
+        { role: 'user', content: 'Follow-up question' },
+      ],
+    });
+  });
+
+  await Sentry.flush(2000);
+}
+
+run();

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

@@ -4,6 +4,7 @@ import {
   GEN_AI_AGENT_NAME_ATTRIBUTE,
   GEN_AI_CONVERSATION_ID_ATTRIBUTE,
   GEN_AI_INPUT_MESSAGES_ATTRIBUTE,
+  GEN_AI_INPUT_MESSAGES_ORIGINAL_LENGTH_ATTRIBUTE,
   GEN_AI_OPERATION_NAME_ATTRIBUTE,
   GEN_AI_PIPELINE_NAME_ATTRIBUTE,
   GEN_AI_REQUEST_AVAILABLE_TOOLS_ATTRIBUTE,
@@ -364,4 +365,37 @@ describe('LangGraph integration', () => {
       await createRunner().ignore('event').expect({ transaction: EXPECTED_TRANSACTION_RESUME }).start().completed();
     });
   });
+
+  const longContent = 'A'.repeat(50_000);
+
+  const EXPECTED_TRANSACTION_NO_TRUNCATION = {
+    transaction: 'langgraph-test',
+    spans: expect.arrayContaining([
+      expect.objectContaining({
+        data: expect.objectContaining({
+          [GEN_AI_INPUT_MESSAGES_ATTRIBUTE]: JSON.stringify([
+            { role: 'user', content: longContent },
+            { role: 'assistant', content: 'Some reply' },
+            { role: 'user', content: 'Follow-up question' },
+          ]),
+          [GEN_AI_INPUT_MESSAGES_ORIGINAL_LENGTH_ATTRIBUTE]: 3,
+        }),
+      }),
+    ]),
+  };
+
+  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();
+      });
+    },
+  );
 });

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

@@ -12,8 +12,12 @@ import {
   GEN_AI_REQUEST_AVAILABLE_TOOLS_ATTRIBUTE,
   GEN_AI_SYSTEM_INSTRUCTIONS_ATTRIBUTE,
 } from '../ai/gen-ai-attributes';
-import { truncateGenAiMessages } from '../ai/messageTruncation';
-import { extractSystemInstructions, resolveAIRecordingOptions } from '../ai/utils';
+import {
+  extractSystemInstructions,
+  getJsonString,
+  getTruncatedJsonString,
+  resolveAIRecordingOptions,
+} from '../ai/utils';
 import type { LangChainMessage } from '../langchain/types';
 import { normalizeLangChainMessages } from '../langchain/utils';
 import { startSpan } from '../trace';
@@ -146,10 +150,12 @@ function instrumentCompiledGraphInvoke(
                 span.setAttribute(GEN_AI_SYSTEM_INSTRUCTIONS_ATTRIBUTE, systemInstructions);
               }
 
-              const truncatedMessages = truncateGenAiMessages(filteredMessages as unknown[]);
+              const enableTruncation = options.enableTruncation ?? true;
               const filteredLength = Array.isArray(filteredMessages) ? filteredMessages.length : 0;
               span.setAttributes({
-                [GEN_AI_INPUT_MESSAGES_ATTRIBUTE]: JSON.stringify(truncatedMessages),
+                [GEN_AI_INPUT_MESSAGES_ATTRIBUTE]: enableTruncation
+                  ? getTruncatedJsonString(filteredMessages)
+                  : getJsonString(filteredMessages),
                 [GEN_AI_INPUT_MESSAGES_ORIGINAL_LENGTH_ATTRIBUTE]: filteredLength,
               });
             }

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

@@ -7,6 +7,11 @@ export interface LangGraphOptions {
    * Enable or disable output recording.
    */
   recordOutputs?: boolean;
+  /**
+   * Enable or disable truncation of recorded input messages.
+   * Defaults to `true`.
+   */
+  enableTruncation?: boolean;
 }
 
 /**