fix(desktop): improve model picker message and runtime dropdown clarity (#778)

desktop/src/features/agents/ui/ModelPicker.tsx

@@ -126,7 +126,16 @@ export function ModelPicker({
             </div>
           ) : !modelsData.supportsSwitching ? (
             <div className="px-3 py-2 text-sm text-muted-foreground">
-              This agent uses the runtime&apos;s default model.
+              {agent.model ? (
+                <>
+                  <p className="font-medium text-foreground">{agent.model}</p>
+                  <p className="mt-0.5 text-xs">
+                    This runtime does not support switching models.
+                  </p>
+                </>
+              ) : (
+                "This agent uses the runtime's default model."
+              )}
             </div>
           ) : (
             <DropdownMenuRadioGroup

desktop/src/features/channels/ui/AddChannelBotDialog.tsx

@@ -563,6 +563,11 @@ export function AddChannelBotDialog({
               </DropdownMenuRadioGroup>
             </DropdownMenuContent>
           </DropdownMenu>
+          <p className="text-xs text-muted-foreground">
+            {selectedPersonas.some((p) => p.provider)
+              ? "Personas with a preferred runtime will use their own instead of this selection."
+              : "Default runtime for all deployed agents."}
+          </p>
         </div>
 
         {teams.length > 0 ? (