# Fix turns left for a custom model

> Set the real context window size for a model, so turns left counts correctly.

**Goal:** make "turns left" correct for a model crystl does not know.

crystl estimates a model's context window from its name. For an unknown model it uses a small default, so "turns left" shows too few turns. Set the real size once:

```bash
crystl model context set glm-4.6 200000
```

Use the model ID your agent reports. The size is a whole number of tokens. It is **free on every tier**.

## What you'll see when it works

crystl prints `Saved. glm-4.6 has a context window of 200,000 tokens.` "Turns left" uses the new size the next time it updates.

To see your sizes, run `crystl model context list`. To go back to the estimate, run `crystl model context remove glm-4.6`.

## Go deeper

- [CLI reference](/docs/cli/#model-context) for every flag.

---
Source: https://crystl.dev/docs/scenario-fix-turns-left/