Model providers (BYOM)

By default, AskUI Desktop runs inference through the AskUI hub, billed to your workspace, nothing to configure. Bring your own model (BYOM) points the agent at a model provider you control instead: your own Anthropic key, any OpenAI‑compatible API, or a self‑hosted server on your network.

Where to configure it

Configure it under Settings → Account → Model Provider, switch an already‑running install to BYOM, or edit/remove an existing configuration.

Choose an API type

Supported models

• Default: claude-sonnet-4-6. Leave the Model field blank on the Anthropic tab and this is what runs.
• Claude models (recommended): the Anthropic Messages API is the tested path, whether you reach it through the AskUI hub, your own Anthropic key, Azure AI Foundry, or an Anthropic-compatible gateway. AWS Bedrock and GCP Vertex AI authenticate differently (SigV4, Google credentials), as do some internal gateways: either put something in front that re-exposes them as an Anthropic- or OpenAI-compatible endpoint, or talk to us and we help you get your authentication scheme supported. Any current Claude model with vision works; ids come from Anthropic's model list. Newer Claude generations also use adaptive thinking automatically.
• GPT-5.4 models: supported through the OpenAI-compatible tab: gpt-5.4, gpt-5.4-mini and gpt-5.4-nano, from OpenAI directly or via OpenRouter. They see screenshots and call tools, so they drive a UI, they're just not the path AskUI tests against.
• Gemini vision models: gemini-2.5-pro, gemini-3-pro-preview and the Flash variants work the same way, as long as your gateway exposes them OpenAI-compatibly (OpenRouter, or your own proxy).
• Self-hosted VLMs: a screen-capable model such as Qwen/Qwen3-VL-… behind vLLM or SGLang, which keeps screenshots inside your own tenancy.
• What won't work: text-only models, and models without tool/function calling. Every action the agent takes is a tool call on a screenshot; without both it cannot execute a step.

Model choice is the main lever on run cost and duration, the trade-offs and what to watch: Performance & cost.

Add a provider

Behind a corporate proxy, configure network access first, the setup wizard's Behind a proxy? Configure network access section, or Settings → Network proxy: otherwise the test call can't reach the endpoint. Details: Network proxy.

Gateway message transforms

Some corporate gateways enforce rules stricter than the stock OpenAI spec, and reject the agent's requests with HTTP 400 even though the model behind them would accept them. For these, an operator project can normalize the outgoing messages array: drop a class implementing IOpenAiMessageTransform into utils/message_transforms/.

public sealed class GatewayNormalization : IOpenAiMessageTransform
{
    public JsonArray Transform(JsonArray messages)
    {
        var output = new JsonArray();
        foreach (var node in messages)
        {
            var message = (JsonObject)node!.DeepClone();
            // Example gateway rule: an assistant message carrying
            // tool_calls must have content = null.
            if ((string?)message["role"] == "assistant"
                && message["tool_calls"] is JsonArray { Count: > 0 })
            {
                message["content"] = null;
            }
            output.Add(message);
        }
        return output;
    }
}

Transform files compile at run start exactly like custom tools, no using directives needed, a compile error aborts the run, and the same rule applies: developer territory. Multiple files compose in discovery order. Only the OpenAI-compatible provider consults them; the app ships no gateway-specific rules, your project owns them.

How your credentials are stored

• The API key is stored encrypted on this device (on Windows, via DPAPI scoped to your user account). The non‑secret fields, provider, model id, base URL, are stored in plain local settings.
• The key is passed to the run in memory and is never written to the run report or logs.
• Editing other fields won't wipe a saved key, leave the key field blank to keep the existing one.

Switching back to the AskUI hub

In Settings → Account → Model Provider, choose Remove key. This reverts to the AskUI hub default and forgets the stored key. (In License mode there is no hub default, so you replace the provider rather than removing it.)