Client · Authorization
Scope union on step-up
When re-authorizing after an insufficient_scope challenge the client requests the union of the scopes it already holds and the newly required ones.
mcp.client.scope-union
In revision 2026-07-28
- Level
- SHOULD
- Defined in
- Authorization › Scope Challenge HandlingMCP Authorization 2026-07-28
- Party
- Client
- Observable
manualRequires reading documentation or source; recorded by people.
Client-side requirement: not shown in the server matrix. It is recorded so later tools can cite it.
Level by revision
| Revision | Level | Section |
|---|---|---|
| 2026-07-28current | SHOULD | Authorization › Scope Challenge Handling |
| 2025-11-25 | SHOULD | Authorization Flow › Scope Challenge Handling |