`sudoc_sru_mcp_lookup_by_isbn` – 1 MCP server offers this tool

What it usually takes

No server marks it as only reading: treat it as able to change data.

From each publisher's own tool list. We never call a tool.

Server	Inputs	Read-only?
Sudoc SRU MCP demo `co.huggingface.geraldine/sudoc-sru-mcp` Fetch the Sudoc records carrying a given ISBN. One ISBN can match several records. Hyphens are optional: "978-2-07-041311-9" and "9782070413119" behave the same. The Sudoc `isb` index covers monographs only; for serials, query the `isn` index through search_sudoc. Returns: {"source": "sudoc-sru", "command": "lookup_by_isbn", "total_found": int, "returned": int, "isbn_queried": str, "results": [<same record shape as search_sudoc>], "error": str \| null}	`isbn`	Not stated