Send the saved main broadcast content to 1-5 explicit recipients without changing the broadcast or sending its audience. Matching workspace contacts personalize the preview. Subject and sender overrides affect only this test. The broadcast must satisfy the dashboard test-send eligibility check independently of overrides; completed, canceled, unhealthy and incomplete broadcasts cannot be tested. Existing preview permissions and workspace/team quotas apply. API and MCP test sends share a limit of 10 requests per minute per user. Submissions are synchronous and ordered; duplicates are separate submissions. HTTP 200 confirms that the existing preview action was created and run. No status resource, inbox tracking or idempotent replay is provided.