The operation was aborted, commonly due to a conflict.
The entity being created already exists.
The caller or owning task cancelled the operation.
Data was corrupted or irrecoverably lost.
The operation did not finish before its deadline.
Runtime state must change before this operation is valid.
An A11 invariant or implementation failed.
Input is invalid regardless of current runtime state.
The requested entity does not exist.
The operation completed successfully.
A requested offset or value lies outside its valid range.
The authenticated caller lacks permission.
A bounded queue, quota, or other resource is exhausted.
The caller's identity could not be established.
A transient service or transport is unavailable.
This endpoint does not implement the requested operation.
No more specific failure code is known.
Portable outcome codes used across actions, stores, transports, and HTTP.
A11 returns these structured outcomes from expected operational failures so an agent can preserve the same meaning across process and language boundaries. Reserve thrown JavaScript errors for code that explicitly opts into the exception helpers below.