{"version":"2.1.287","anchor":"mcp-tools-can-defer-all-tools-and-tools-may-overlap","canonical_anchor":"mcp-tools-can-defer-all-tools-and-tools-may-overlap","heading":"MCP servers can hold back all their tools, and some tools can run side by side","tier":"notice","area":"MCP","scope":null,"heads_up":null,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.287\/e\/mcp-tools-can-defer-all-tools-and-tools-may-overlap","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.287","markdown":"### MCP servers can hold back all their tools, and some tools can run side by side\n\nAn MCP server can now hold back all its tools from loading up front, and more MCP tools can count as safe to run in parallel\n\n**Unclear.** It is not clear what marks a server as deferring all its tools or a call as allowed to overlap.\n\n**What**\n\nMCP servers are outside programs that give Claude Code extra tools. Claude Code can hold some tools back until they are needed, finding them through tool search. Two things change:\n\n- When a server is marked as deferring all its tools, none of them are loaded up front, even ones that would otherwise always load.\n\n- A tool now counts as safe to run alongside other tools if it is read-only, as before, or if its call is marked as allowed to overlap.\n\nListing resource templates (patterns describing data a server offers) is now limited to servers that pass a configuration check.\n\n**Why**\n\nThis changes which MCP tools Claude sees from the start and which can run at the same time.\n\n- Area: MCP\n- Tier: You'll notice\n- Useful: 3\/5\n- Signal: 2\/5"}