Classify embedding failures at the provider level

app/MindWork AI Studio/Provider/ProviderRequestFailureReason.cs

@@ -14,4 +14,56 @@ public enum ProviderRequestFailureReason
     /// meant to answer for it does not offer it.
     /// </remarks>
     MODEL_NOT_SUPPORTED_BY_PROVIDER,
+
+    /// <summary>
+    /// No usable API key was available, or the provider rejected the one we sent.
+    /// </summary>
+    /// <remarks>
+    /// Both cases lead to the same place for the user: the key stored for this provider is not
+    /// one the provider works with, and the settings are where they fix it.
+    /// </remarks>
+    INVALID_OR_MISSING_API_KEY,
+
+    /// <summary>
+    /// The key was accepted, but the account is not allowed to do what we asked for.
+    /// </summary>
+    /// <remarks>
+    /// Typical causes are a key without the required scope, a model the account has no access
+    /// to, and providers which refuse requests from the user's region.
+    /// </remarks>
+    AUTHENTICATION_OR_PERMISSION_ERROR,
+
+    /// <summary>
+    /// The provider could not be reached, or said that it cannot serve requests right now.
+    /// </summary>
+    PROVIDER_UNAVAILABLE,
+
+    /// <summary>
+    /// The provider does not know the requested model at all.
+    /// </summary>
+    MODEL_NOT_FOUND,
+
+    /// <summary>
+    /// The text we sent was longer than the model accepts.
+    /// </summary>
+    CONTEXT_LENGTH_EXCEEDED,
+
+    /// <summary>
+    /// The provider cannot create embeddings at all.
+    /// </summary>
+    EMBEDDINGS_NOT_SUPPORTED,
+
+    /// <summary>
+    /// The provider answered successfully, but with something we were not able to read.
+    /// </summary>
+    INVALID_RESPONSE,
+
+    /// <summary>
+    /// The request failed and we were not able to tell why.
+    /// </summary>
+    /// <remarks>
+    /// Deliberately without a user message of its own: what the provider itself said about the
+    /// failure tells the user more than a sentence which says nothing.
+    /// </remarks>
+    UNKNOWN,
 }