# 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.