Finding / cursor
2026-09-21-cursor-hooks-beforemcpexecution-gains-server-identity-and-the-doc-tells-allowlist-hooks-to-deny
Hooks: beforeMCPExecution gains server identity, and the doc tells allowlist hooks to deny on missing names. Before, a hook could only tell which MCP server a call targeted by matching a URL or a free-form command string. Now there is a stable server key.
Channel: docs-only. Half: both. Date: between 2026-08-20 and 2026-09-02 (bracketed by captures).
Operator consequence: Re-audit any MCP allowlist hook: if it matches on command, it can be evaded by a server launched with a different path or via ${CURSOR_PLUGIN_ROOT} expansion. Switch to mcp_server_name + tool_name, and fail closed when the field is absent (older client builds). Enterprise-managed hooks now reach self-hosted workers, so a managed hook is a control on those machines too.
Receipt
Finding metadata
Run: 2026-09-21-weekly-digest-2026-08-20_2026-09-21-frontier-v0
Finding ID: 2026-09-21-cursor-hooks-beforemcpexecution-gains-server-identity-and-the-doc-tells-allowlist-hooks-to-deny
Profile citations
- cursor / claim / mcp-hook-server-identity
Source links
Primary links, including exact changelog lines when available.
- official docs2026-09-21-cursor-hooks-beforemcpexecution-gains-server-identity-and-the-doc-tells-allowlist-hooks-to-denyweb.archive.org/web/20260820212459/https://cursor.com/docs/hooksofficial docs2026-09-21-cursor-hooks-beforemcpexecution-gains-server-identity-and-the-doc-tells-allowlist-hooks-to-denyweb.archive.org/web/20260902233313/https://cursor.com/docs/hooks