Claude Code's Tool Search feature (shipped January 2026, now on by default) defers all MCP tool definitions and injects a single search tool instead, dropping token overhead from ~51K tokens (7 MCP servers) to ~8.5K—an 85% reduction with no configuration required. When Claude needs a tool, it searches by keyword and selectively loads 3-5 relevant definitions per query; the feature auto-activates when total tool descriptions exceed 10K tokens. This directly extends the effective working context budget for agentic sessions that rely heavily on MCP servers.