# Symptom

After upgrading to LangChain v1, your stream-event filtering by node name `"agent"` stops matching. No error; events just never match.

## Confirm

Log the raw stream chunk names. You will see `"model"` where `"agent"` used to be.

## Cause

v1 renamed the streaming node from `"agent"` to `"model"` as part of the create_agent migration.

## Fix

Update every filter, match, and branch that references the old node name:

- `"agent"` -> `"model"` in stream chunk filtering.

## Verify

Re-run the stream and confirm your handler now receives the model-step events. Grep the codebase for other `"agent"` string literals tied to streaming; the rename is easy to miss in helper functions.