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DisclaimerUnofficial, and not affiliated with Anthropic. Nearly all of this is read straight out of what ships: npm bundles, captured prompts, published docs. Anthropic's own notes go in verbatim, marked as theirs. The rest is my reading, and every entry carries the strings behind it. If one looks wrong, vote it down and say why.

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Claude Code v2.1.239

Administrators can forbid server-delivered MCP servers with disableSideloadFlags

Use it now
Useful3 Signal3
MCP Notable

Admins can set disableSideloadFlags to block --mcp-config and refuse MCP servers pushed in from outside your config.

disableSideloadFlags--mcp-config
What

A managed setting can now refuse MCP servers pushed in from outside your own config. When disableSideloadFlags is set, the CLI warns that --mcp-config is forbidden on the machine and drops server-delivered MCP servers with a stated reason instead of loading them.

Details
  • The reason string is "disableSideloadFlags policy", alongside the existing safe-mode and hermetic-mode refusal reasons.
  • Dropped servers are reported as "Ignored: managed setting disableSideloadFlags forbids server-delivered MCP servers on this machine".
  • Off unless an administrator sets the policy in managed settings.
Evidence

disableSideloadFlags policy

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

See this entry in the whole of v2.1.239 →