MCP tool search solves the "my MCP server has 80 tools" problem. Tools are loaded on demand instead of all at once.

What it does

When a server has tool search enabled, Claude Code sees a searchable index rather than every tool loaded into context. The model queries the index when it needs a tool, loads the matching tool's schema, and calls it. You keep the expressive power of large tool suites without paying tokens for every tool, every turn.

When to use it

Any MCP server exposing more than a handful of tools.
Multi-server setups where combined tool count bloats context.
Cost-sensitive workflows where tool schemas were eating the budget.
Large internal platforms with hundreds of operations.

Gotchas

Tool search adds a small latency for the first call to each tool.
Search queries affect tool selection quality. Servers should provide good descriptions.
Not every MCP server supports deferred loading yet - check the server docs.

Official docs: https://code.claude.com/docs/en/mcp.md#scale-with-mcp-tool-search