We set Agents → Settings → Sharing to No users so people can't org-share Agent Builder agents. Makers still share with named colleagues, and old shared agents still work. Did we misconfigure it — or is Sharing narrower than it sounds?

Sharing setting is Agent Builder only; No users blocks org-wide links, not 1:1 share; existing access stays — Steady.

Does turning off agent Sharing stop Agent Builder sprawl?

You’re not misreading the UI — you’re bumping into what the control actually covers. “No users” sounds like a freeze; Microsoft shipped something subtler.

Here’s what’s going on. Under Agents → Settings → Sharing, admins choose All users (default), Specific users, or No users. Learn is clear on three limits. First, Sharing control only applies to agents built with Microsoft Copilot Agent Builder — it is not the master switch for Copilot Studio, SharePoint agents, or external publishers. Second, No users disables org-wide sharing (the maker’s Org-wide sharing for chat access toggle greys out) but users can still share directly with specific individuals. Third, changes apply only to new sharing actions; existing shared agents remain accessible unless you manually update those sharing settings — and if policies tighten, makers may need to bring an agent into compliance before they can update it further. Org-wide chat sharing is what puts an Agent Builder agent into broader Agent Store discoverability; person-to-person Can chat / Can edit shares are a different path. Agents still respect Graph permissions on knowledge — sharing the agent doesn’t invent SharePoint rights the recipient never had — but embedded files and automatic file-share prompts can still widen the blast radius if makers aren’t careful.

Steady before scale here is Pane 04 plus honest change management: dial org-wide sharing down for Wave 0, then clean the backlog of already-shared agents instead of assuming the setting rewound history. Schofield’s Third Law (historically attributed) fits — org-wide links make access easy for everyone, including people who shouldn’t have the pattern yet.

Options that actually work:

Set Sharing to Specific users (champions / CoE) or No users for Wave 0. Stop new org-wide store links; allow intentional 1:1 shares inside known teams. Best Steady default while you inventory.
Pair the setting with registry hygiene. Filter shared / ownerless Agent Builder agents; reassign or block; require catalog submit + admin publish for anything that must be tenant-discoverable. Complements Sharing.
Assume No users revoked every past share and blocked all Studio agents. It didn’t — you’ll brief the board with fiction.
Leave All users and hope etiquette holds. Third Law says it won’t once someone finds the org-wide toggle.

12 Panes action / comms: Tell makers: No users = no org-wide store link; named shares still work; old shares stay until you change them. Tell Security: this setting is Agent Builder only — Studio still needs environments, DLP, and Requests. Leadership: sharing policy is forward-looking; backlog needs a reclaim sprint.

Benefits / risks: Stops casual tenant-wide Agent Builder promotion without killing collaboration; 1:1 shares and legacy access can still sprawl; Studio/SharePoint paths bypass this dial; makers hit “can no longer update agent” banners when policy and existing share settings conflict.

I’d suggest this week: set Sharing to Specific users or No users, export or filter currently shared Agent Builder agents, and reclaim anything without a living owner — then one FAQ line so Security stops expecting a single toggle to do three jobs. You’ll have Steady sharing without theatre.

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