Architecture Development Notes

Oct 25, 2026 · Operations

Claude Code 2.1.305: Managed stdio Servers with Env-Only Variables Bypass Allowlist Checks

This article analyzes the Claude Code 2.1.305 change where managed-mcp.json stdio servers using variables only in env no longer undergo allowedMcpServers checks, detailing the version history, matching logic, verification commands, and how to block them using deniedMcpServers.