# 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.