Errors and safe retry

Screen commands

A screen command returns a ProjectVResult. When IsSuccess is false, show Message; it is already written for players. The view updates through Observe, so there is nothing else to render.

var result = await shop.PurchaseAsync(offerId, quantity);
if (this != null && !result.IsSuccess)
{
    ShowMessage(result.Message);
}

Presenter commands

A presenter command returns a ProjectV*CommandResult with IsSuccess and the latest Snapshot. Render the snapshot, then the error:

var result = await startup.StartAsync(contentReady: true, token);
Render(result.Snapshot);

if (!result.IsSuccess)
{
    ShowLocalized(result.Snapshot.Error?.LocalizationKey, result.Snapshot.Error?.RequestId);
}

An exception means a programming mistake (a bad argument, a presenter used from the wrong scene), not a server failure. Do not use exceptions for normal control flow.

What to show

The error has	Show
LocalizationKey (Startup, Authentication, Account, Lobby presenter)	Look it up in the game's localization; fall back to a generic message
SafeMessage (data screens, Gameplay data)	Show it as is, or map Code to your own text

Put RequestId in a support or details panel; it lets the SDK team find the request. Never show or log tokens, passwords or raw server responses.

Cancellation

Presenter commands take a CancellationToken; tie it to the page, for example MonoBehaviour.destroyCancellationToken. Screen commands take none: check that the page still exists before using their result.

Cancelling only stops your wait. It does not undo an action the server may already have applied.

When to retry

Situation	Do
A first load failed	Offer Retry
The server rejected an action	Show the reason; do not resend automatically
An action timed out or its result is unknown	Do not send a new one; wait for the screen to update, then let the player decide
Mission settlement failed	Keep the result screen open and retry the same completion
ContractMismatch at startup	Block; the build and the backend do not match
Session expired	Go back through Login

Never resend a purchase, upgrade or claim because the first call timed out, and never write an endless retry loop in a view.

See Troubleshooting for setup and runtime problems.