Extending FunctionGemma for Practical On-Device Mobile Function Calling

Ali Rezagholizadeh, Soheila Samiee


Abstract
On-device assistants require function-calling models that map natural language to local system actions, but existing resources emphasize web APIs or narrow mobile-action catalogs. We extend FunctionGemma 270M-it to practical Android workflows by introducing MOBILEACTIONSEXTENDED, a synthetic, schema-validated dataset of ∼9,500 conversations covering fifteen device-control categories, including messaging, phone calls, camera/screenshot, brightness control, device-status queries, flashlight control, and application management. We fine-tune the 270Mmodel with TRL supervised fine-tuning under completion-only loss, producing an extended specialist and a combined model trained jointly with Google’s MOBILEACTIONSGOOGLE. On MOBILEACTIONSEXTENDED, end-to-end accuracy improves from 29.3% for the base model and 17.2% for Google’s Mobile-Actions variant to 76.5%. The combined model retains 76.5% on MOBILEACTIONSEXTENDED and reaches 82.3% on MOBILEACTIONS-GOOGLE, down from the 90.3% of Google’s Mobile-Actions specialist, representing an 8.0-percentage-point trade-off in return for doubling category coverage. We release the dataset, fine-tuned models, reproducible training/evaluation pipeline, and an Android demo, highlighting compact local function calling as a practical path towards low-latency and privacy-preserving mobile assistants.
Anthology ID:
2026.emnlp-industry.170
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing: Industry Track
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Pepa Atanasova, Gholamreza Haffari, Minghan Wang
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
2889–2904
Language:
URL:
https://aclanthology.org/2026.emnlp-industry.170/
DOI:
Bibkey:
Cite (ACL):
Ali Rezagholizadeh and Soheila Samiee. 2026. Extending FunctionGemma for Practical On-Device Mobile Function Calling. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing: Industry Track, pages 2889–2904, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Extending FunctionGemma for Practical On-Device Mobile Function Calling (Rezagholizadeh & Samiee, EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-industry.170.pdf