[FEATURE]:Add mcp search tool, reduce mcp tool occupying a lot of context #8625

Feature hasn't been suggested before.

• I have verified this feature I'm about to request hasn't been suggested before.

Describe the enhancement you want to request

When MCP tool descriptions exceed 10% of the context window, they are automatically deferred and discovered via the MCPSearch tool instead of being loaded upfront. This reduces context usage for users with many MCP tools configured.

I found this great tool in Claude code, which I feel can make open code even more powerful