ORA-2026-0031: Tool triage — ignore MCP generic fallbacks

ORA-2026-0031: Tool triage — ignore MCP generic fallbacks

Rule

MCP servers inject tools at connect time. Generic tools (ListMcpResourcesTool, ReadMcpResourceTool) are fallbacks — ignore them. Use execute_sql for schemas, Read for files, named tools for everything else.

If an unfamiliar tool appears after MCP reconnect or plugin load, check whether a tool you already have covers the same function before investigating. Investigation is expensive; most injected tools are generic fallbacks for capabilities you already have through named tools.

Evidence

A Claude session on 2026-04-18 encountered ListMcpResourcesTool and ReadMcpResourceTool after an MCP server reconnect. The session spent investigation cycles determining what the tools do, whether they were needed, and writing up an insight — only to conclude they were unnecessary because execute_sql, Read, and named MCP tools already cover every use case.

The friction pattern: unfamiliar tool appears → no boot surface guidance → session defaults to investigation → burns context → concludes "not needed." Every session that encounters these tools pays this cost independently.

Principle

When an unfamiliar tool appears, the correct default is "check if something you already have covers it," not "investigate what it does." This applies to all providers (Claude, Codex, Gemini) — MCP tool injection is provider-agnostic.