> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://docs.nvidia.com/nemo/gym/v0.5.1/nemo-gym/nemo_gym/models/token_capture/llms.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://docs.nvidia.com/nemo/gym/_mcp/server.

# nemo_gym.models.token_capture

Provide the core training-token capture interfaces.

Training capture is separate from evaluation capture.
Middleware sets a request-scoped token sink.
The model server records a `TokenEntry` from its complete response.
Consumers call `TokenSource.freeze` for an atomic snapshot.
The snapshot includes entries and incomplete state.
Its `snapshot_id` identifies the exact frozen state.
`TokenCaptureStore` is Gym's local sink and source implementation.
Framework transports may provide their own sink and source.
`finalize_rollout_token_capture` rebuilds one rollout record from its frozen snapshot.
The incomplete state prevents training on a rollout that lost a model call.
Finalization freezes and rebuilds the rollout.
Finalization does not retire the snapshot.
The caller retires it only after durable handoff.
Retirement uses the frozen `snapshot_id` and version.
Failed or masked builds retain their capture evidence.

This package is token capture's public API.
Code outside `nemo_gym/` imports token capture names from `nemo_gym.models.token_capture`,
not from `nemo_gym.models`.
Every name it serves imports without Gym's server stack or an OpenAI client,
because frameworks implement its protocols.
Framework token staging has a public API of its own, `nemo_gym.models.token_capture.staging`.

## Subpackages

* **[`nemo_gym.models.token_capture.adapters`](/nemo/gym/nemo-gym/nemo_gym/models/token_capture/adapters)**
* **[`nemo_gym.models.token_capture.staging`](/nemo/gym/nemo-gym/nemo_gym/models/token_capture/staging)**

## Submodules

* **[`nemo_gym.models.token_capture.builder`](/nemo/gym/nemo-gym/nemo_gym/models/token_capture/builder)**
* **[`nemo_gym.models.token_capture.completion`](/nemo/gym/nemo-gym/nemo_gym/models/token_capture/completion)**
* **[`nemo_gym.models.token_capture.config`](/nemo/gym/nemo-gym/nemo_gym/models/token_capture/config)**
* **[`nemo_gym.models.token_capture.conformance`](/nemo/gym/nemo-gym/nemo_gym/models/token_capture/conformance)**
* **[`nemo_gym.models.token_capture.consumer`](/nemo/gym/nemo-gym/nemo_gym/models/token_capture/consumer)**
* **[`nemo_gym.models.token_capture.control_routes`](/nemo/gym/nemo-gym/nemo_gym/models/token_capture/control_routes)**
* **[`nemo_gym.models.token_capture.delivery`](/nemo/gym/nemo-gym/nemo_gym/models/token_capture/delivery)**
* **[`nemo_gym.models.token_capture.external_capture`](/nemo/gym/nemo-gym/nemo_gym/models/token_capture/external_capture)**
* **[`nemo_gym.models.token_capture.fingerprint`](/nemo/gym/nemo-gym/nemo_gym/models/token_capture/fingerprint)**
* **[`nemo_gym.models.token_capture.lineage`](/nemo/gym/nemo-gym/nemo_gym/models/token_capture/lineage)**
* **[`nemo_gym.models.token_capture.protocols`](/nemo/gym/nemo-gym/nemo_gym/models/token_capture/protocols)**
* **[`nemo_gym.models.token_capture.records`](/nemo/gym/nemo-gym/nemo_gym/models/token_capture/records)**
* **[`nemo_gym.models.token_capture.replay`](/nemo/gym/nemo-gym/nemo_gym/models/token_capture/replay)**
* **[`nemo_gym.models.token_capture.sink`](/nemo/gym/nemo-gym/nemo_gym/models/token_capture/sink)**
* **[`nemo_gym.models.token_capture.store`](/nemo/gym/nemo-gym/nemo_gym/models/token_capture/store)**
* **[`nemo_gym.models.token_capture.terminal`](/nemo/gym/nemo-gym/nemo_gym/models/token_capture/terminal)**

## Package Contents

### Data

[`_PUBLIC_API`](#nemo_gym-models-token_capture-_PUBLIC_API)

### API

```python
nemo_gym.models.token_capture._PUBLIC_API = {'CAPTURE_REFUSAL_HEADER': 'protocols', 'CONTEXT_LENGTH_EXCEEDED_ERROR_CODE': 'r...
```

## Docs

- [nemo_gym.models.token_capture.adapters](https://docs.nvidia.com/nemo/gym/v0.5.1/nemo-gym/nemo_gym/models/token_capture/adapters.md)
- [nemo_gym.models.token_capture.adapters.megatron](https://docs.nvidia.com/nemo/gym/v0.5.1/nemo-gym/nemo_gym/models/token_capture/adapters/megatron.md)
- [nemo_gym.models.token_capture.adapters.vllm](https://docs.nvidia.com/nemo/gym/v0.5.1/nemo-gym/nemo_gym/models/token_capture/adapters/vllm.md)
- [nemo_gym.models.token_capture.builder](https://docs.nvidia.com/nemo/gym/v0.5.1/nemo-gym/nemo_gym/models/token_capture/builder.md)
- [nemo_gym.models.token_capture.completion](https://docs.nvidia.com/nemo/gym/v0.5.1/nemo-gym/nemo_gym/models/token_capture/completion.md)
- [nemo_gym.models.token_capture.config](https://docs.nvidia.com/nemo/gym/v0.5.1/nemo-gym/nemo_gym/models/token_capture/config.md)
- [nemo_gym.models.token_capture.conformance](https://docs.nvidia.com/nemo/gym/v0.5.1/nemo-gym/nemo_gym/models/token_capture/conformance.md)
- [nemo_gym.models.token_capture.consumer](https://docs.nvidia.com/nemo/gym/v0.5.1/nemo-gym/nemo_gym/models/token_capture/consumer.md)
- [nemo_gym.models.token_capture.control_routes](https://docs.nvidia.com/nemo/gym/v0.5.1/nemo-gym/nemo_gym/models/token_capture/control_routes.md)
- [nemo_gym.models.token_capture.delivery](https://docs.nvidia.com/nemo/gym/v0.5.1/nemo-gym/nemo_gym/models/token_capture/delivery.md)
- [nemo_gym.models.token_capture.external_capture](https://docs.nvidia.com/nemo/gym/v0.5.1/nemo-gym/nemo_gym/models/token_capture/external_capture.md)
- [nemo_gym.models.token_capture.fingerprint](https://docs.nvidia.com/nemo/gym/v0.5.1/nemo-gym/nemo_gym/models/token_capture/fingerprint.md)
- [nemo_gym.models.token_capture.lineage](https://docs.nvidia.com/nemo/gym/v0.5.1/nemo-gym/nemo_gym/models/token_capture/lineage.md)
- [nemo_gym.models.token_capture.protocols](https://docs.nvidia.com/nemo/gym/v0.5.1/nemo-gym/nemo_gym/models/token_capture/protocols.md)
- [nemo_gym.models.token_capture.records](https://docs.nvidia.com/nemo/gym/v0.5.1/nemo-gym/nemo_gym/models/token_capture/records.md)
- [nemo_gym.models.token_capture.replay](https://docs.nvidia.com/nemo/gym/v0.5.1/nemo-gym/nemo_gym/models/token_capture/replay.md)
- [nemo_gym.models.token_capture.sink](https://docs.nvidia.com/nemo/gym/v0.5.1/nemo-gym/nemo_gym/models/token_capture/sink.md)
- [nemo_gym.models.token_capture.staging](https://docs.nvidia.com/nemo/gym/v0.5.1/nemo-gym/nemo_gym/models/token_capture/staging.md)
- [nemo_gym.models.token_capture.staging.capture](https://docs.nvidia.com/nemo/gym/v0.5.1/nemo-gym/nemo_gym/models/token_capture/staging/capture.md)
- [nemo_gym.models.token_capture.staging.conformance](https://docs.nvidia.com/nemo/gym/v0.5.1/nemo-gym/nemo_gym/models/token_capture/staging/conformance.md)
- [nemo_gym.models.token_capture.staging.digest](https://docs.nvidia.com/nemo/gym/v0.5.1/nemo-gym/nemo_gym/models/token_capture/staging/digest.md)
- [nemo_gym.models.token_capture.staging.protocols](https://docs.nvidia.com/nemo/gym/v0.5.1/nemo-gym/nemo_gym/models/token_capture/staging/protocols.md)
- [nemo_gym.models.token_capture.staging.rebuild](https://docs.nvidia.com/nemo/gym/v0.5.1/nemo-gym/nemo_gym/models/token_capture/staging/rebuild.md)
- [nemo_gym.models.token_capture.staging.records](https://docs.nvidia.com/nemo/gym/v0.5.1/nemo-gym/nemo_gym/models/token_capture/staging/records.md)
- [nemo_gym.models.token_capture.staging.routes](https://docs.nvidia.com/nemo/gym/v0.5.1/nemo-gym/nemo_gym/models/token_capture/staging/routes.md)
- [nemo_gym.models.token_capture.staging.terminal](https://docs.nvidia.com/nemo/gym/v0.5.1/nemo-gym/nemo_gym/models/token_capture/staging/terminal.md)
- [nemo_gym.models.token_capture.store](https://docs.nvidia.com/nemo/gym/v0.5.1/nemo-gym/nemo_gym/models/token_capture/store.md)
- [nemo_gym.models.token_capture.terminal](https://docs.nvidia.com/nemo/gym/v0.5.1/nemo-gym/nemo_gym/models/token_capture/terminal.md)