2026-10-24-github-copilot-cli-managed-policy-docs-accept-registry-style-mcp-names-and-add-a-base64-image-requirement

Managed-policy docs accept registry-style MCP names and add a base64 image requirement. The documented MCP allowlist name grammar expands to accept dots and slashes, including registry-style microsoft/playwright-mcp names; matching remains case-sensitive and non-wildcard. A new requireBase64ImageAttachments managed key requires base64 attachments when true and leaves existing behavior when false/unset. A server name remains a user-chosen label, not an authenticated identity.

Channel: docs-only. Half: both. Date: 2026-10-20.

Operator consequence: Review managed lists that renamed registry servers merely to satisfy the older grammar, then test an allowed and denied server on the deployed runtime before removing the workaround. Prefer URL or exact command matching when identity matters. For image-handling policy, validate both URL and base64 requests before adopting the new key; the docs addition alone does not establish a minimum client version.

Receipt

• https://github.com/github/docs/commit/92991ed6d17c5023f52e324ee70d36fe7c36dd7d
• https://github.com/github/docs/blob/02c25d16369fe27f9bdb28d1201f6b452f0d21dd/content/copilot/reference/copilot-cli-reference/cli-config-dir-reference.md#L678
• https://github.com/github/docs/blob/02c25d16369fe27f9bdb28d1201f6b452f0d21dd/content/copilot/reference/copilot-cli-reference/cli-config-dir-reference.md#L755-L775
• https://github.com/github/docs/blob/02c25d16369fe27f9bdb28d1201f6b452f0d21dd/content/copilot/reference/enterprise-administrators/enterprise-managed-settings.md#L353-L360