Fix: a batch carrying a modern-envelope request is rejected -32600

Web-audit fix skill for the mcp-batch-reject check (MCP, SHOULD).

Goal

Refuse JSON array batches that carry modern-era envelopes with -32600.

Fix

Reject a JSON array batch whose element carries the modern params._meta envelope (protocol revision 2026-07-28) with error.code: -32600 (Invalid Request) and id: null. Modern-era requests are single-request only: an envelope-bearing element inside an array is never valid, so serving it (or answering anything other than -32600) is non-conforming.

Resources

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

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-batch-reject check should report pass.