Update dataset card

README.md

@@ -34,13 +34,14 @@ one ``(instance_id, test_id)`` trace.
 
 ## Schema
 
+Trace shards under `data/`:
+
 | column | type | notes |
 | --- | --- | --- |
 | `instance_id` | string | SWE-rebench-V2 row id |
 | `test_id` | string | pytest node id |
 | `affected` | bool | True = test touched by the PR patch; False = broad-phase test |
 | `text` | string | plain-text annotated source + execution trace |
-| `license` | string | license of the source repository, joined from SWE-rebench V2 by `instance_id` |
 
 `affected=True` rows render as ``<test source>`` / ``# --- pre-patch trace ---``
 / ``# --- patch ---`` / ``# --- post-patch trace ---``; `affected=False` rows
@@ -49,6 +50,38 @@ render as ``<test source>`` / ``# --- trace ---``.
 Sentinel rows from instances that failed before any trace was captured are
 excluded.
 
+## Joining the per-instance license
+
+`metadata/licenses.parquet` is a companion file mapping `instance_id` ->
+`license` (the source repository's license at the instance commit). It is kept
+separate so the multi-GB trace shards do not carry a redundant per-row string.
+Join it on `instance_id` to attach the license to any trace row.
+
+With `datasets`:
+
+```python
+from datasets import load_dataset
+
+REPO = "marin-community/swe-rebench-v2-CodeWorldModeling"
+
+traces = load_dataset(REPO, split="train")
+licenses = load_dataset(REPO, data_files="metadata/licenses.parquet", split="train")
+
+license_by_instance = dict(zip(licenses["instance_id"], licenses["license"]))
+traces = traces.map(lambda row: {"license": license_by_instance[row["instance_id"]]})
+```
+
+With pandas:
+
+```python
+import pandas as pd
+
+base = "hf://datasets/marin-community/swe-rebench-v2-CodeWorldModeling"
+traces = pd.read_parquet(f"{base}/data")
+licenses = pd.read_parquet(f"{base}/metadata/licenses.parquet")
+traces = traces.merge(licenses, on="instance_id", how="left")
+```
+
 ## Provenance
 
 - **Source dataset**: [`nebius/SWE-rebench-V2`](https://huggingface.co/datasets/nebius/SWE-rebench-V2)
@@ -64,9 +97,10 @@ This dataset is derived from SWE-rebench V2 and inherits its license terms:
 > particular instance is based. To facilitate this, the license of each
 > repository at the time of the commit is provided for every instance.
 
-The per-instance source-repository license is included here directly as the
-`license` column. When using or redistributing these traces, honor the license
-of the originating repository for each instance.
+The per-instance source-repository license is provided in the companion file
+`metadata/licenses.parquet` (join on `instance_id`). When using or
+redistributing these traces, honor the license of the originating repository
+for each instance.
 
 ## Citation