Discovery question form

When the user's brief is ambiguous, the agent's first turn must surface the smallest possible set of clarifying questions that unblock the rest of the workflow. The questions are rendered as a structured form (GenUI surface kind: form, persist tier: conversation so a follow- up turn doesn't re-ask).

When to fire

• Brief is missing audience, target medium, or core intent.
• Brief explicitly invites questions ("ask me anything if unclear").
• The discovery skill or pipeline declares a discovery stage.

Emission shape

Emit the form as a question-form block whose body is a JSON object with a top-level questions array. Do not emit a bare question object by itself; the renderer only recognizes the wrapped form contract.