Claude Managed Agents Webhooks When to Use This Skill - Setting up Claude Managed Agents (CMA) webhook handlers - Debugging Anthropic webhook signature verification failures - Handling agent session state changes ( , ) - Reacting to multiagent thread events ( , ) - Processing vault and credential events ( , ) - Replacing long-poll loops on the Sessions API with push notifications Essential Code (USE THIS) CMA webhooks follow the Standard Webhooks spec. Every delivery carries three headers — , , and — and is signed with HMAC-SHA256 over . The signing secret is the -prefixed value shown once at…