Role-Based Access Control: One Decision Gates Every Document, Cell, and AI Answer

Most finance tools bolt permissions onto whatever surface needed them at the time: one rule for who can open a document, another for who can edit a model cell, a third, usually looser, for what an AI assistant is allowed to see when it answers a question. That gap between “what the person can view” and “what the AI reasons over” is where most so-called permission systems quietly leak. Rexfin closes it by routing every read (document, model cell, provenance link, AI query) through a single access decision.

The building blocks

Access in Rexfin composes from four things, evaluated together rather than separately.

Role is the coarse layer: admin, contributor, or viewer. Admins manage members, folders, and exports. Contributors edit the model (drivers, scenarios, forecast cells) inside the folders they can reach. Viewers read: they can see the model, open the provenance drawer, and read cited AI answers, but they cannot change anything, ever, regardless of which folders they can open.

Side matters more than it sounds like it should. A deal has sell-side, buy-side, and neutral members. Sell-side admins bypass folder restrictions, because an owner should never get locked out of their own workspace. Buy-side admins do not get that bypass: two competing bidders on the same deal must stay walled off from each other, and an “admin” badge on one bidder’s team should never be a backdoor into the other’s restricted folders.

Groups let an admin grant or deny access to a whole team at once (a bidder’s diligence team, a workstream) without editing permissions member by member. Add someone to the group and their folder access updates immediately; remove them and it revokes immediately.

Phase gates staged disclosure. As a deal advances (say, from indication of interest to bid stage), a buyer’s assigned phase advances too, and folders tagged to later phases open up automatically. Nobody has to remember to flip individual permissions at every milestone.

One function decides, everything else obeys

All four dimensions feed a single access check per folder. The order matters: an explicit deny always beats an allow, a phase gate blocks before any allow rule is even considered, and a folder with no rules configured inherits the member’s deal-level role rather than defaulting open or closed unpredictably. If none of that resolves cleanly, the default is deny. Not “deny unless we forgot to think about it”: deny is the answer when nothing else applies.

The reason this is worth explaining rather than assuming is what it gates. The same folder decision governs the document itself, the extracted line items sourced from it, and the click-to-source links in the model. There’s no separate, looser rule for “can the AI see this”: when Rexfin’s assistant answers a question, its retrieval is restricted to exactly the same set of documents the asking member could open by hand. Ask about a figure sitting in a folder you don’t have access to, and the assistant won’t paraphrase it, won’t cite it, and won’t hint at it: it refuses because that evidence was never in its retrievable set to begin with. That is the property most AI tools quietly get wrong: hiding a document from the UI while still feeding it to the model as context is a leak with a polite face on it.

What this makes possible

For a diligence process with multiple competing bidders, this means you can run one workspace instead of parallel data rooms, because the segregation is structural rather than a matter of remembering which spreadsheet went to which team. For a company board, it means a contributor role can build the model without ever touching who’s in the room. And when someone does need to check who could see what and when, that’s not a guess: every access, grant, denial, and role change is written to the audit trail, so “who was allowed to see this number” has an answer that isn’t “we think so.”

None of this replaces judgment about who should have a given role. Rexfin enforces the rule once it’s set; deciding whether your new hire should be a contributor or a viewer is still a human call. What the system removes is the risk that the rule is enforced inconsistently depending on which screen someone happens to be looking at, including the AI’s.

If you’re evaluating Rexfin for a live deal with real access boundaries (sell-side, multiple bidders, staged disclosure), book a demo and we’ll walk through the folder structure with your actual team roster. For the rest of the product tour, start at the pillar hub.