LLM completion refused

A text completion the model declined to write, or that a provider's safety filter stopped.

A provider answers such a completion as a success, often with no text at all and sometimes with the beginning of one, and a stop value saying why it ended: content_filter on OpenAI chat completions and on an incomplete Responses API answer, refusal on Anthropic, content_filtered and guardrail_intervened on Bedrock, and on Gemini SAFETY, RECITATION, PROHIBITED_CONTENT, BLOCKLIST, SPII and their kin. A Gemini prompt blocked before the model wrote anything comes back with no candidate at all and its reason in the prompt feedback, prompt_feedback.block_reason, such as SAFETY or PROHIBITED_CONTENT: it is a refusal too, whatever the reason, and the error names that reason as its stop value. The worker raises this error instead of handing the text back, so the pipe fails rather than passing an empty or cut text for a result.

The message names the model by its deck handle, the pipe and the stop value, then the next step:

The model 'claude-5-sonnet' declined to finish the text of pipe 'ui_designer', or a content filter stopped it (stop reason 'content_filtered'), so the text cannot be used. Revise the pipe's prompt or its input.

A run reports it located at the failing pipe, Pipe 'ui_designer' failed (flow → ui_designer): The model …. The partial text and the provider's body never appear in it.

What to do. Revise the pipe's prompt or its input: rephrase what triggered the refusal, or remove the content the filter stopped on. Another model, whose policy or filter differs, may also answer.

For an agent. Branch on the report's fields: error_type is LLMCompletionRefusedError, error_category is content, error_domain is input (an HTTP surface answers 422), retryable is false, since the same request is refused the same way, and user_action.kind is change_input. The message is caller-facing, so it survives STRICT disclosure.

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