# Symptom
```
TypeError: create_agent() got an unexpected keyword argument 'prompt'
```
## Confirm
Look at the create_agent call. It passes `prompt=`.
## Cause
In v1 the parameter was renamed from `prompt` to `system_prompt`, and it now takes a plain string. If you passed a SystemMessage object, extract the string from its content.
## Fix
```python
agent = create_agent(
model="gpt-5.5",
tools=[...],
system_prompt="You are a helpful assistant", # was prompt=
)
```
For dynamic prompts (changing per turn or per user), do not pass a function as the prompt. Use the `@dynamic_prompt` middleware decorator with `context_schema` instead; that is the v1 replacement for callable prompts.
## Verify
The agent constructs and invokes. Grep for other `prompt=` uses on create_agent / create_react_agent calls in the repo; they all need the rename.