In the Model Context Protocol (MCP), permissions are managed through a combination of role-based policies and explicit access control lists (ACLs). Permissions are granted by assigning roles or attributes to users, services, or components, which define their access rights within a specific context. For example, a developer might assign a “data-reader” role to a service account, allowing it to query specific datasets. Revoking permissions typically involves removing these roles or updating ACLs to exclude the entity from the allowed set. MCP often uses declarative configuration files or APIs to enforce these rules, ensuring consistency across environments. This approach centralizes permission management, reducing the risk of manual errors.
A common method for granting permissions in MCP is through policy definitions. For instance, a YAML configuration might define that any user in the “admin” group can modify system settings, while “contributors” can only submit changes for review. When a user’s role changes—say, from “contributor” to "admin"—the system updates their permissions automatically based on the revised policy. Similarly, API endpoints like PUT /roles/{user-id} might programmatically assign roles. Access can also be scoped to specific resources, such as granting read access to a particular database table. These granular controls ensure that permissions align with the principle of least privilege, limiting exposure to unintended actions.
Revocation in MCP is often immediate and enforced through real-time policy checks. If a user leaves a project, their associated roles are removed via a command like DELETE /roles/{user-id}, stripping access to related resources. Alternatively, time-bound permissions might expire automatically, such as a temporary “debug-access” role that deactivates after 24 hours. MCP systems may also integrate with auditing tools to detect and revoke unused or overly broad permissions. For example, an automated scan might flag accounts with stale admin privileges and trigger revocation workflows. This combination of manual and automated processes ensures permissions remain aligned with current requirements while minimizing security gaps.