{"version":"2.1.251","anchor":"mcp-tool-calls-can-no-longer-spawn-subagents-mid-call","canonical_anchor":"mcp-tool-calls-can-no-longer-spawn-subagents-mid-call","heading":"MCP tool calls can no longer spawn subagents mid-call","tier":"notice","area":"MCP","scope":null,"heads_up":null,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.251\/e\/mcp-tool-calls-can-no-longer-spawn-subagents-mid-call","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.251","markdown":"### MCP tool calls can no longer spawn subagents mid-call\n\nAn MCP tool call can no longer start a subagent Task while it runs.\n\n**What**\n\nMCP tool invocations dispatched over the SDK control channel now run with subagent spawning disabled, so a tool call cannot start a Task while it is running.\n\n**Details**\n\n- Unconditional on this path.\n\n**Evidence**\n\n`disallowTasks: !0`\n\n- Area: MCP\n- Tier: You'll notice\n- Useful: 3\/5\n- Signal: 3\/5"}