instrumentLangGraph input/output recording only works with MessagesAnnotation #19628

Is there an existing issue for this?

• I have checked for existing issues https://github.com/getsentry/sentry-javascript/issues
• I have reviewed the documentation https://docs.sentry.io/
• I am using the latest SDK release https://github.com/getsentry/sentry-javascript/releases

How do you use Sentry?

Sentry Saas (sentry.io)

Which SDK are you using?

@sentry/browser

SDK Version

^10.40.0

Framework Version

No response

Link to Sentry event

https://pri-dogfooding-ai.sentry.io/insights/ai-agents/?project=4510951776059472&statsPeriod=30d&trace=5eb7a6719e6a45dd8b4accab1881c7bd&span=a2fd3ab2120a6698&trace-timestamp=1772622965

Reproduction Example/SDK Setup

No response

Steps to Reproduce

const CustomState = Annotation.Root({
  idea: Annotation(),
  expanded: Annotation(),
  validated: Annotation(),
});

const graph = new StateGraph(CustomState)
  .addNode("expand", expandNode)
  .addEdge(START, "expand")
  .addEdge("expand", END);

Sentry.instrumentLangGraph(graph, { recordInputs: true, recordOutputs: true });
const compiled = graph.compile({ name: "my_agent" });
const result = await compiled.invoke({ idea: "test idea" });

Expected Result

The invoke_agent span should contain the graph's input ({ idea: "test idea" }) and output state as span attributes.

Actual Result

The invoke_agent span has no input or output data. No error or warning is logged.

Additional Context

instrumentCompiledGraphInvoke hardcodes extraction for MessagesAnnotation:

const inputMessages = args.length > 0 ? ((args[0])?.messages ?? []) : [];

It looks for args[0].messages, which only exists when using MessagesAnnotation. Custom state keys (like idea, expanded, etc.) are ignored. The OTEL gen_ai.input.messages / gen_ai.output.messages attributes are message-array-oriented by design, but there is no fallback to record arbitrary state.

Priority

_{React with 👍 to help prioritize this issue. Please use comments to provide useful context, avoiding +1 or me too, to help us triage it.}