Document SPARC VQA prompting and model mixtures

README.md

@@ -32,6 +32,20 @@ SPARC VQA is the generated spatial VQA training dataset used in the SPARC Qwen3.
 
 See [irl-kit/SPARC-VQA-Mixture](https://huggingface.co/datasets/irl-kit/SPARC-VQA-Mixture) for the reproducible mixture manifest. The released models are [Qwen3.5-4B](https://huggingface.co/irl-kit/SPARC-Qwen3.5-4B), [Qwen3.5-0.8B-VTFT](https://huggingface.co/irl-kit/SPARC-Qwen3.5-0.8B-VTFT), and [Qwen3.5-9B-EO](https://huggingface.co/irl-kit/SPARC-Qwen3.5-9B-EO).
 
+## Prompting compatibility
+
+The released models are sensitive to output formatting. Use each model's bundled chat template with a single user turn containing the image followed by the question. For point prediction, use this suffix:
+
+```text
+Output the point coordinates in JSON format like [{"point_2d": [x, y], "label": "target"}]. Use integer coordinates between 0 and 1000.
+```
+
+For trajectories or multiple points, use this suffix:
+
+```text
+Return only a JSON list like [{"point_2d": [x1, y1], "label": "point_1"}, {"point_2d": [x2, y2], "label": "point_2"}, ...]. Use integer coordinates between 0 and 1000.
+```
+
 ## Citation
 
 ```bibtex