Fix: modern resources/read with an unknown URI returns -32602

Web-audit fix skill for the mcp-modern-resources-miss check (MCP, SHOULD).

Goal

Answer an unknown resource URI with the typed miss code, not a hang or a fake result.

Fix

Answer a modern resources/read (with Mcp-Name mirroring params.uri) for a URI that matches no resource with error.code: -32602. That is the code current SDK lines put on the wire for a resource miss; -32002 (the legacy resource-not-found code) is also tolerated from non-SDK servers. A hang, a 500, or a fabricated 200 result fails. This check only runs when the server advertises resources on either era lane.

Resources

• MCP resources (2026-07-28)
• JSON-RPC 2.0

Copy-paste prompt

Paste this into your coding agent. Your audit adds what it observed for this check:

Verify

Re-run the audit at https://anc.dev/audit or call the audit_website MCP tool; the mcp-modern-resources-miss check should report pass.