An MCP server your allowlist left out can now load. Claude Code 2.1.305 did it.

By Lior AharonovFounder, 7IT Solutions · 21 October 2026

What happened

As of 21 October 2026, Claude Code 2.1.305 is the latest tag on npm. Its changelog says allowedMcpServers no longer filters managed-mcp.json stdio servers that use ${VAR} only in env, so a server the allowlist left out now loads on upgrade. Another fix stops a same-named server from your own settings replacing one passed by a cloud session or setMcpServers.

Why it matters

Picture an admin who left your stdio server off the allowlist. After the upgrade it loads anyway, unless a deny rule says no. And a server handed in by a cloud session keeps its place, even when local settings carry the same name.

What to do

If you manage Claude Code settings, add deniedMcpServers entries for any managed-mcp.json stdio server that must stay off, then retest after upgrading to 2.1.305.

An allowlist that quietly changes meaning is not a wall. Read the changelog before you trust the fence.

Lior Aharonov · my take

Sources

Claude Code changelog at v2.1.305 (anthropics/claude-code) raw.githubusercontent.com
npm dist-tags: @anthropic-ai/claude-code registry.npmjs.org

claude-codepermissionsmanaged-settingsnpm

Researched with AI tools; every fact is checked against the linked sources.