Why is search mode the default?
In full mode, the agent loads every tool’s schema on every turn. With a large catalog, that fills the agent’s context window before it has done any work, and the client must expose every tool whether the agent needs it or not. Search mode keeps the agent’s working set fixed at five small tools. The agent searches for and loads only the schemas it actually needs, one task at a time. When a client asks you to approve each tool by name, search mode asks once per runner — once for reads, once for writes — rather than once per tool. The tradeoff is an extra search step; the gain is that context size stays constant as your catalog grows. Use full mode when your client’s permission rules or hooks match tool names, since in search mode every call goes through a runner and a per-tool rule no longer fires.Does search mode change which tools I can call?
No. Search mode reaches exactly the tools full mode lists for you. A call you could not make in full mode is refused in search mode too — the same permission check, credential, and rate limit apply.Does search mode support prompts and resources?
Yes. Prompts and resources work the same as in full mode. Search mode changes only how the client discovers tools, not what the gateway supports.Can the catalog be out of date?
Yes, briefly. The catalog search can trail a server that just changed. When you must know exactly what is callable right now, usemcp__describe_tools directly against a named server, or tools/list in full mode. A match in search results never grants permission to run a tool.
What if search doesn’t find the right tool?
Search matches your query against each tool’s name, description, and server name using full-text search, not a language model, so it matches words not meaning. If a search misses, rephrase with words the tool’s description is likely to use, or usemcp__describe_tools to list a server’s tools directly by passing the server name.