{"version":"2.1.288","anchor":"mcp-tasks-changed-host-rejection-added-handler-registered","canonical_anchor":"mcp-tasks-changed-host-rejection-added-handler-registered","heading":"New service message telling cloud agents that MCP tasks changed","tier":"internal","area":"MCP","scope":"individual","heads_up":false,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.288\/e\/mcp-tasks-changed-host-rejection-added-handler-registered","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.288","markdown":"### New service message telling cloud agents that MCP tasks changed\n\nClaude Code recognises a new `mcp_tasks_changed` message that only the service may send to cloud agents; programs hosting Claude Code are refused\n\n**Unclear.** What Claude Code does on receiving this message, and who sends it, were not established.\n\n**What**\n\nClaude Code now recognises a control message called `mcp_tasks_changed`. MCP (Model Context Protocol) is the way Claude Code connects to outside tools, and the message name suggests it reports a change in tasks from those tools.\n\nA host, meaning a program driving Claude Code, is not allowed to send this message. If one tries, it is refused with the error \"mcp_tasks_changed is sent to a cloud agent by the service, not by a host\", the same rule that already covered `stage_file` and `turn_handoff`. Claude Code also registers a handler for the message when it does arrive.\n\n**Why**\n\nThis looks like groundwork for the service to notify cloud agents about MCP task changes. Programs that host Claude Code cannot use it.\n\n- Area: MCP\n- Tier: Under the hood\n- Useful: 2\/5\n- Signal: 3\/5\n- Scope: individual\n- Heads-up: no"}