What are default-deny permissions?
Default-deny permissions is a security model in which a user, system or AI agent starts with no access at all. Every app, record type and action must be explicitly granted, so anything not on the allow list is blocked automatically.
How it works
Under default-deny, the starting state is zero. An administrator then grants specific permissions, such as reading contacts in the CRM, drafting but not sending email, or updating one field on a deal. Requests outside those grants fail.
The opposite model, default-allow, starts open and blocks known risks. It is easier to set up but leaves gaps whenever someone forgets to add a rule. Default-deny trades a little setup time for far fewer surprises.
Why it matters for AI agents
AI agents act quickly and can be asked to do things nobody planned for. With default-allow, a vague instruction might lead an agent to read sensitive files or change records outside its job. With default-deny, it simply cannot.
This model also makes reviews easier. Instead of asking what an agent might be able to reach, a reviewer reads a short list of what it was granted. That list maps directly to the agent's responsibilities and to audit requirements.
Object-level permissions
Default-deny works best when grants are precise. Object-level permissions let an administrator allow access to specific types of records, such as leads but not opportunities, or tickets but not billing data, and to specific actions on each, such as read, create or update.
Precise grants keep an AI worker useful without giving it the whole system. As its responsibilities grow, new permissions are added one at a time, each with a clear reason.
Questions
Is default-deny the same as least privilege?
They are closely related. Least privilege is the principle that every account should have only the access it needs. Default-deny is a practical way to enforce it, because access starts at zero and each permission must be justified and granted explicitly. Together they limit the damage any single account can do.
Does default-deny make AI agents harder to set up?
Slightly, at the start. You have to decide which apps and records each agent needs. That step pays off quickly: the agent's scope is documented, reviews are faster, and a confusing request cannot lead it into data or actions outside its job.
Related terms
Updated October 2026