{"version":"2.1.321","anchor":"mcp-schema-memory-guard","canonical_anchor":"mcp-schema-memory-guard","heading":"MCP tools with oversized schemas are dropped instead of using too much memory","tier":"notice","area":"MCP","scope":"individual","heads_up":true,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.321\/e\/mcp-schema-memory-guard","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.321","markdown":"### MCP tools with oversized schemas are dropped instead of using too much memory\n\nAn MCP tool is left out if combining its schema options would take too much memory because of numeric property names\n\n**What**\n\nMCP servers are outside programs that give Claude Code extra tools, and each tool describes its inputs in a schema. Some schemas offer several alternative shapes, which Claude Code combines into one. If that combining would take too much memory because the schema uses numeric property names, Claude Code now drops the tool.\n\n**Why**\n\nIf an unusual MCP tool goes missing, this can be why. Claude Code shows a message saying the tool would take too much memory.\n\n- Area: MCP\n- Tier: You'll notice\n- Useful: 2\/5\n- Signal: 1\/5\n- Scope: individual\n- Heads-up: yes"}