# Importing a capture

Use **Export trace** to download a complete working example. The same JSON imports into this viewer. Import reads the file locally and never sends its contents to a server. Closing the tab discards imported state.

Supported schemas are `flint.trace.v1` for Flint and `model.trace.v1` for Flint or Qwen. Legacy Flint exports without `model` metadata remain supported. Both registered checkpoints use Q8_0. A different architecture or quantization requires a separate registry entry and compatible measurements.

A trace contains:

| Field | Contents |
| --- | --- |
| `schema` | Supported schema identifier |
| `model` | Model identity and quantization; `id` is `flint` or `qwen` |
| `architecture` | Text-decoder configuration matching `models.json` |
| `prompt` | Original prompt, up to 4000 characters |
| `settings` | Recorded output limit, temperature, seed and reasoning flag |
| `start.tokens` | Decoded input-token pieces, including chat-template tokens |
| `frames` | 1 to 256 output-token frames, in generation order |

Each frame records `text`, `token_id`, optional raw UTF-8 `token_bytes`, `input_position`, `duration`, `elapsed`, and one entry per decoder block in `layers`. `input_position` begins at `start.tokens.length - 1` and increases by one. It identifies the input that predicted this frame's output token. Capture context is limited to 2048 positions.

Every layer includes finite, nonnegative `heads`, `ffn` and `residual` RMS measurements. Head count follows the layer type. Flint MoE layers add six unique `experts`, six normalized `weights`, and `shared` and `routed` output RMS. Its first two layers are dense.

Attention layers include one `attention` entry per head, with `top` position/probability pairs, `entropy`, and Flint's `sink` probability. Only the strongest eight positions are retained. Recurrent layers instead include `write_gate`, `retention`, and `state_rms` arrays per value head.

The viewer checks all frames and relevant architecture dimensions before changing the loaded trace. It accepts stopped captures containing valid complete frames. It rejects empty captures, malformed JSON, inconsistent model identity and invalid measurement dimensions. Files larger than 160 MB are rejected before parsing.

A compatible exporter must record actual tensors from an instrumented model execution. An ordinary text completion does not supply attention, routing or recurrent-state measurements. The bundled captures provide concrete, downloadable examples of the complete format.