Raise Content Filter Error

RaiseContentFilterError is a capability that opts into treating any model response with finish_reason='content_filter' as a ContentFilterError, even when the provider returns partial text or refusal text:

raise_content_filter_error.py

from pydantic_ai import Agent
from pydantic_ai.capabilities import RaiseContentFilterError
from pydantic_ai.exceptions import ContentFilterError
from pydantic_ai.messages import ModelMessage, ModelResponse, TextPart
from pydantic_ai.models.function import AgentInfo, FunctionModel


def filtered_response(messages: list[ModelMessage], info: AgentInfo) -> ModelResponse:
    return ModelResponse(
        parts=[TextPart(content='I cannot help with that.')],
        finish_reason='content_filter',
        provider_details={'finish_reason': 'content_filter'},
    )


agent = Agent(FunctionModel(filtered_response), capabilities=[RaiseContentFilterError()])

try:
    agent.run_sync('Tell me how to make a weapon.')
except ContentFilterError as exc:
    print(exc.message)
    #> Content filter triggered. Finish reason: 'content_filter'

(This example is complete, it can be run “as is”)

By default, Pydantic AI only raises ContentFilterError when a content_filter response is empty: if the provider returns partial text or refusal text alongside finish_reason='content_filter', that text becomes ordinary agent output and no error is raised (see finish reason handling). This capability extends the check to every content_filter response, so partial and refusal text raise too. When it raises, the full ModelResponse is serialized into ContentFilterError.body so the partial text remains inspectable.