MCP: Reduce token-heavy outputs + document tool output format

MCP tools can be inefficient with token usage. For example, List Resources may return extremely large outputs (hundreds of thousands of characters / thousands of lines), exceeding model tool limits and causing agents to resort to brittle grepping/jq workarounds.

Please introduce more token-safe defaults (pagination/limits/filtered output) and improve documentation explaining the tool output format so this doesn’t happen.

Example: Listing resources could return a small summary by default instead of 14k+ lines.