> ## Documentation Index
> Fetch the complete documentation index at: https://docs.arouter.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Zero Completion Insurance

> ARouter does not charge for requests where the model returns zero output tokens due to an error or provider-side failure. Enabled by default.

Zero Completion Insurance is a default protection that ensures you are never charged for requests where the model fails to produce any output due to a provider-side error.

## How It Works

If a response meets **all** of the following criteria, the request is not charged:

1. `usage.completion_tokens == 0` (the model produced no output tokens)
2. `finish_reason` is empty, `null`, or `"error"`
3. The failure originated on the provider side (not from an invalid request)

In these cases, `usage.cost` is returned as `0` and no credits are deducted from your account.

## What's Covered

| Scenario                                            | Covered?           |
| --------------------------------------------------- | ------------------ |
| Provider timeout with no output                     | Yes                |
| Provider internal error (5xx)                       | Yes                |
| Model refused to respond (safety filter, 0 tokens)  | Yes                |
| `max_tokens: 1` with 0 completion tokens returned   | No (valid request) |
| Your request had an error (invalid model, bad JSON) | No (client error)  |

## Viewing Protected Requests

In the [Activity](https://arouter.ai/activity) page, requests protected by Zero Completion Insurance show:

* `cost: $0.00`
* `finish_reason: error` or `finish_reason: null`
* `completion_tokens: 0`

You can filter by `cost = 0` and `completion_tokens = 0` to audit these requests.

## No Configuration Required

Zero Completion Insurance is always active. There is no parameter to enable or disable it. If you believe a request should have been covered but wasn't, contact [support@arouter.ai](mailto:support@arouter.ai) with the generation ID from your Activity log.

## Related

* [Error Handling](/en/guides/error-handling) — How to handle provider errors in your application
* [Activity Export](/en/guides/administration/activity-export) — Export usage data for analysis
* [Billing & Credits](/en/guides/billing-and-credits) — How ARouter billing works