<!-- https://zerolog.ch/docs/helper-models · Docs / Keys and privacy -->
# Helper and checking models

> With your own key, the small jobs around a chat run on your provider.

**With your own key, the small jobs around a chat run on your provider.** Before, several of them quietly switched to a platform model or failed.

- Helper jobs are summaries of long chats, [/goal](https://zerolog.ch/docs/goal) checks, Deep Research helpers, memory suggestions, the prompt improver, the design loop, the site builder, the Ultracode planner and reducer, the tool checker, second opinions from another model, Buddy, legal questions, Smart Auto and the small model of the terminal agent.
- On your own key they run on a helper model of that provider. Your provider bills them, so they need no ZeroLog credit and a balance of zero does not stop them.
- The default is a small, fast model from the list your key offers. For Anthropic it is Claude Haiku 5.5. For the others ZeroLog picks the smallest model of the newest family with names such as nano, mini, flash, small or haiku. If your key lists no small model, the run model does the job itself.
- You can choose another model per connected provider under Settings, Advanced, **Helper model with your own key**. The model that describes pictures for text-only models is set there too.
- A chat on a platform model keeps its Featherless helper. The penetration test keeps its fixed Featherless list on purpose.

## The checking model of an Ultracode or goal run

- On your own key the checker can be any model on your keys or a Featherless model. On the platform it must be a Featherless model. Models of other platform providers are refused.
- The check happens at the start, also for the price estimate. A checker that is not allowed is refused at once, and the answer lists up to eight allowed models, the closest first.
- A checker on your own key counts as zero platform cost.

We tested this with a replica of the provider lists. We have not yet run every helper against a real key of each of the 25 providers, so the default for providers other than Anthropic depends on what your key lists.

See [your own API key](https://zerolog.ch/docs/byok) and [/ultracode](https://zerolog.ch/docs/ultracode).

## Which model does the helper jobs

Mermaid source of the diagram on this page:

```mermaid
%% Helper and checking models: which model does the small jobs. Facts from server/pruefmodell.js (hilfsmodellFuer, PRUEF_STANDARD, pruefModellErlaubt).
flowchart TB
  job["A chat starts a helper job<br/>summary, /goal check, planner,<br/>checker, memory, second opinion"]
  own["Chat on your own key"]
  plat["Chat on a platform model"]
  set["Your setting for that provider<br/>Settings, Advanced"]
  def["No setting: a small model from<br/>your key's list<br/>Anthropic: Claude Haiku 5.5"]:::hot
  run["Runs on your key<br/>billed by the provider<br/>no ZeroLog credit"]
  fe["Featherless helper<br/>as before"]

  job --> own
  job --> plat
  own --> set
  set -->|"chosen"| run
  set -->|"not set"| def
  def --> run
  plat --> fe

  linkStyle 4 stroke:#8f7ac9
  linkStyle 5 stroke:#8f7ac9

  classDef hot stroke:#8f7ac9
```