{"slug":"mcp-tool-search-cost","verification":{"valid":true,"entries":7,"head":"9a805b4c32ab0a01be2a312cc930b2ce5bc8df33f0de6d9f2b7360f0fce70b62"},"energy":{"passes":7,"tokens_in":0,"tokens_out":0,"tokens_total":0,"cost_usd":0,"models":{"Opus 5 (Claude Code)":7},"head":"9a805b4c32ab0a01be2a312cc930b2ce5bc8df33f0de6d9f2b7360f0fce70b62"},"provenance":[{"ts":"2026-07-26T03:31:42.091Z","model":"Opus 5 (Claude Code)","action":"sources","prompt":"","input":"mcp-tool-search-cost","response":"6 source(s) added","tokens_in":0,"tokens_out":0,"cost":0,"prev":"genesis","hash":"470e607ec744bd1186383ea0ae74ebe087e17244f528188307ee3b3d407832fc"},{"ts":"2026-07-26T03:31:42.597Z","model":"Opus 5 (Claude Code)","action":"claim","prompt":"","input":"mcp-tool-search-cost c1","response":"Claude Code sends every MCP tool definition in every request by default: 856 definitions measured on one machine, reduced to 9 plus a ToolSearch tool by ENABLE_TOOL_SEARCH=true.","tokens_in":0,"tokens_out":0,"cost":0,"prev":"470e607ec744bd1186383ea0ae74ebe087e17244f528188307ee3b3d407832fc","hash":"0fe1fc6c79ce6b257430d620e2d34eda1c2ff1f58acb5cbae577aa73ddcc56d6"},{"ts":"2026-07-26T03:31:43.034Z","model":"Opus 5 (Claude Code)","action":"claim","prompt":"","input":"mcp-tool-search-cost c2","response":"With the same MCP server attached, tool search cut a measured turn from 149,187 input tokens and $0.02852109 to 14,109 tokens and $0.00443075.","tokens_in":0,"tokens_out":0,"cost":0,"prev":"0fe1fc6c79ce6b257430d620e2d34eda1c2ff1f58acb5cbae577aa73ddcc56d6","hash":"24c17ce15f3760cdbed7775ed8a754bd78292e7d93e8aecaf33936f9cc8cd457"},{"ts":"2026-07-26T03:31:43.458Z","model":"Opus 5 (Claude Code)","action":"claim","prompt":"","input":"mcp-tool-search-cost c3","response":"Tool search on is cheaper per turn than disconnecting the MCP server entirely, which measured 21,928 input tokens and $0.01089448.","tokens_in":0,"tokens_out":0,"cost":0,"prev":"24c17ce15f3760cdbed7775ed8a754bd78292e7d93e8aecaf33936f9cc8cd457","hash":"0e4cdc469fb6c5831ecbfc20ab2ca4f86ead0394369e4155885a70a9c5656046"},{"ts":"2026-07-26T03:31:43.894Z","model":"Opus 5 (Claude Code)","action":"claim","prompt":"","input":"mcp-tool-search-cost c4","response":"A non-Anthropic model drives the deferred-tool loop: Kimi K2.7 Code called ToolSearch for a tool it had not been shown, invoked it, and returned its payload.","tokens_in":0,"tokens_out":0,"cost":0,"prev":"0e4cdc469fb6c5831ecbfc20ab2ca4f86ead0394369e4155885a70a9c5656046","hash":"9fedf1cb137ba8ba375635fe23c3d55b52cafa54e1270b03c544769b816e32a8"},{"ts":"2026-07-26T03:31:44.654Z","model":"Opus 5 (Claude Code)","action":"claim","prompt":"","input":"mcp-tool-search-cost c5","response":"Anthropic's prompt-caching page and Moonshot's Claude Code guide both state that tool search is unavailable or unsupported, which contradicts the measurement on claude-cli 2.1.165.","tokens_in":0,"tokens_out":0,"cost":0,"prev":"9fedf1cb137ba8ba375635fe23c3d55b52cafa54e1270b03c544769b816e32a8","hash":"40e972ee5fe175ecaf58b98add24e725abd388bdf797d0fa98dedb0470310104"},{"ts":"2026-07-26T03:31:45.388Z","model":"Opus 5 (Claude Code)","action":"claim","prompt":"","input":"mcp-tool-search-cost c6","response":"The measurement method is published, so any reader can re-derive the tool counts on their own client version with two commands.","tokens_in":0,"tokens_out":0,"cost":0,"prev":"40e972ee5fe175ecaf58b98add24e725abd388bdf797d0fa98dedb0470310104","hash":"9a805b4c32ab0a01be2a312cc930b2ce5bc8df33f0de6d9f2b7360f0fce70b62"}]}