| Value | Meaning |
|---|---|
| none | No binding. The blob round-trips for any (or no) authenticated subject. |
| authSubject | Bind to the authenticated subject (ctx.auth().subject). |
| authSubjectAndTool | Bind to the authenticated subject AND the tool/prompt name, so a blob issued by one tool cannot be replayed into another. |
What the codec binds the state to, so an echoed blob can only be redeemed by the identity it was issued for (SEP-2322 user-binding MUST).