Your own LLM provider

Before you begin

For an API connection, you need an account with the chosen provider and its API key. A ChatGPT subscription and the OpenAI API are separate services: ChatGPT Plus by itself does not create an OpenAI API key or API credit.

Secure storage

When Assistela asks where to store passwords and access keys, choose Use Mac keychain for normal use. Assistela Data is easier to back up, but the data becomes more sensitive when it contains keys.

OpenAI, Anthropic, or another listed provider

1

Add an AI account

Open Assistela → Settings → AI Accounts. Click + at the lower left and choose your provider.

2

Check the API server

For listed providers, the API server address on the Account tab is prefilled. Do not change it unless the provider explicitly gives you a different address.

3

Paste the API key

In Access key, paste the API key exactly as shown in the provider dashboard. Do not add spaces or quotation marks.

4

Save and check

Click Save and check account. Wait for a message saying the account is ready or the connection works.

5

Select a model

Open the Model tab. Keep the preset model, or refresh the model list and choose another. Enter a model name manually only when the provider does not return it in the list.

6

Make it the default

On the Account tab, click Set as default. Then send a test message in Chat.

Custom OpenAI-compatible or Anthropic-compatible API

From the + menu, choose Custom OpenAI-compatible or Custom Anthropic-compatible. The server address is not filled in for a custom account.

In API server address, enter the complete URL from your provider documentation. An OpenAI-compatible API often includes a path such as /v1, but the specific provider documentation is authoritative.
Confirm the correct connection format: OpenAI API format or Anthropic Messages API format.
Paste the API key and click Save and check account.
On the Model tab, load the model list. If the API does not provide a list, choose a custom model and enter the exact model ID.

ChatGPT subscription without an API key

1

Choose ChatGPT subscription

Under Settings → AI Accounts, click + and choose ChatGPT subscription.

2

Start the connection

Click Connect ChatGPT. Assistela shows a one-time code.

3

Open OpenAI

Use Open OpenAI page and Copy code. On the opened page, sign in to the correct ChatGPT account and enter the code.

4

Wait for confirmation

Return to Assistela and keep the window open. The app checks the connection automatically for several minutes. If a button to confirm that you entered the code appears, use it.

5

Make it the default

After the connection succeeds, click Set as default and test Chat.

Common problems

Invalid key: create or copy the API key again, then save the account again.
Invalid API server address: check https://, the API path, and any final /v1 against the provider documentation.
Model not found: refresh the model list or enter the exact model ID.
The account works but Chat does not use it: make the account the default and confirm that it is enabled.

Choosing a model without complex tuning

For the main account, start with a model that the provider says supports tool calling. If Chat answers but cannot use Calendar, email, or other actions, verify tool support before changing advanced token settings.

Use a capable general model as the default for Chat and complex work.
A cheaper fast model can suit frequent simple automatic checks.
After changing the model, use Save and check account, then test one safe read-only action.

See Model Routing to split work across multiple models.