goose with SeibertGPT

Desktop app with chat and agent – set up the provider with a few clicks, ideal for getting started.

Beginnertested with goose 1.52.0 on September 26, 2026 · all tools

1. Prerequisites

You need a SeibertGPT plan and an API key. You get both after signing in.

2. Download for macOS

  • Open the zip and drag “Goose” into the “Applications” folder.
  • On first launch, confirm “Open” if asked.

3. Set up

Add the provider in goose

Menu at the top left → Settings → “Models” tab → “Configure providers” → at the very bottom “Add Custom Provider”. Enter these values and click “Create Provider”:

Provider Type
OpenAI Compatible
Display Name
SeibertGPT
API URL
https://api.seibert.ai/v1
API Key
your SeibertGPT key (sgpt_…)
Available Models
deepseek-v41-flash, deepseek-v41-flash-fast, deepseek-v41-flash-low, deepseek-v41-flash-high, deepseek-v41-flash-max
Streaming Support
on

Choose the model

At the bottom of the chat window, choose “SeibertGPT” and the model deepseek-v41-flash-fast. goose stores the key in the Keychain.

Optional: your plan's context limit

The GUI doesn't set a context limit (goose then assumes 128,000). For 1,000,000 tokens, download the file below and put it in the folder shown – it replaces the provider from the GUI; enter the key under “Configure” for the SeibertGPT provider.

File: ~/.config/goose/custom_providers/custom_seibertgpt.json · Download custom_seibertgpt.json

custom_seibertgpt.json
{
  "name": "custom_seibertgpt",
  "engine": "openai",
  "display_name": "SeibertGPT",
  "description": "SeibertGPT – DeepSeek, operated in the EU",
  "api_key_env": "CUSTOM_SEIBERTGPT_API_KEY",
  "base_url": "https://api.seibert.ai/v1",
  "models": [
    {
      "name": "deepseek-v41-flash",
      "context_limit": 1000000,
      "supports_vision": true
    },
    {
      "name": "deepseek-v41-flash-fast",
      "context_limit": 1000000,
      "supports_vision": true
    },
    {
      "name": "deepseek-v41-flash-low",
      "context_limit": 1000000,
      "supports_vision": true
    },
    {
      "name": "deepseek-v41-flash-high",
      "context_limit": 1000000,
      "supports_vision": true
    },
    {
      "name": "deepseek-v41-flash-max",
      "context_limit": 1000000,
      "supports_vision": true
    }
  ],
  "supports_streaming": true,
  "requires_auth": true,
  "dynamic_models": false
}

4. Test

Type “Hello, who are you?” – you'll get an answer within a few seconds.

5. Troubleshooting

“No api key passed in”

Enter the key again under “Configure” for the SeibertGPT provider.

Provider missing after downloading the file

Restart goose; the file must be named exactly custom_seibertgpt.json.

HTTP 401 – key rejected

The key was copied incorrectly or has been revoked. Create a new key under Account → API keys.

HTTP 403 – IP binding

Your key is currently bound to a different IP (e.g. another device). Wait for the lock period to expire or release the binding under Account → API keys.

HTTP 413 – cold_request_too_large

A new or long-paused session starts with a lot of context. Start a new session or shorten the history.

“Hinweis von SeibertGPT: Der Kontext ist zu … gefüllt” (German context notice)

You're approaching your plan's context limit. Summarize the history (e.g. /compact) or start over.

Nothing works after an update

These tools change quickly. The version the guide was tested with is shown at the top – let us know if something no longer matches.