"Tool selection gets less reliable past 30–50 tools, and past about 10 tools or 10K tokens of definitions you should already defer most of them behind tool search. Solutions:
- (1)Tool routing — a fast classifier (Flash) categorizes the query first, then only relevant tools (5-8) are attached for that category.
- (2)Tool groups — separate MCP servers by domain (billing tools, support tools, analytics tools). Attach only the relevant server per task.
- (3)Better descriptions — include 'when NOT to use this tool' in the description. Be explicit: 'Use get_account for account metadata. Do NOT use this for billing data — use get_billing instead.'
- (4)Few-shot examples — in the system prompt, show 2-3 examples of correct tool selection for common query types."