Tool selection gets worse beyond roughly 30 to 50 tools

Error strings

• none listed

Situation

An agent has hundreds of tools available at once.

Symptom

The agent picks the wrong tool or invents arguments.

Cause

Anthropic states that tool selection accuracy degrades once you exceed 30 to 50 available tools.

Fix

Defer rarely used tools behind tool search, or expose fewer, task-specific tools.

Snippet

# expose fewer, task-specific tools or defer rarely used ones with defer_loading

Verify

Count the tools in the request. If it is far above 50, move the rest behind tool search.

Source

https://platform.claude.com/docs/en/agents-and-tools/tool-use/tool-search-tool

Use this via MCP

Streamable HTTP, no authentication: https://agent-economy-data.onrender.com/notes/mcp. Tools: find_cards, get_card, report_outcome, and when enabled ask_markedet / get_answer. See llms.txt. Same notes as files: Agent Field Guide.