{"version":"2.1.275","anchor":"attachment-builder-drops-a-tool-availability-gate-around-pen","canonical_anchor":"attachment-builder-drops-a-tool-availability-gate-around-pen","heading":"Attachment builder drops a tool-availability gate around pending MCP names","tier":"internal","area":"MCP","scope":null,"heads_up":null,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.275\/e\/attachment-builder-drops-a-tool-availability-gate-around-pen","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.275","markdown":"### Attachment builder drops a tool-availability gate around pending MCP names\n\nPending MCP server names are now always included when building tool-availability updates\n\n**Unclear.** The finding does not say what visible difference this makes to the tools Claude sees during a session.\n\n**What**\n\nThe code that builds the list of tool changes sent to Claude (the \"deferred tools delta\") used to only include the names of pending MCP clients (external tool servers still connecting) when a certain tool-availability check was false. That check has been removed, so pending MCP client names are now always included. A related `keepMcp` flag used when stripping tools is also now hard-coded to `true`.\n\n**Why**\n\nThis means information about MCP servers that are still connecting is passed through more consistently, though the finding doesn't specify the downstream effect of always including it.\n\n- Area: MCP\n- Tier: Under the hood\n- Useful: 1\/5\n- Signal: 1\/5"}