Hammer: Robust Function-Calling for On-Device Language Models via Function Masking
On the map: LLM agents and tool use → Tool learning and function calling
Abstract (arXiv)
Large language models have demonstrated impressive value in performing as autonomous agents when equipped with external tools and API calls. Nonetheless, effectively harnessing their potential for executing complex tasks crucially relies on enhancements in their function calling capabilities. This paper identifies a critical gap in existing function calling models, where performance varies significantly across benchmarks, often due to being misled by specific naming conventions. To address such an issue, we introduce Hammer, a novel family of foundation models specifically engineered for on-device function calling. Hammer employs an augmented dataset that enhances models' sensitivity to irrelevant functions and incorporates function masking techniques to minimize misleading. Our empirical evaluations reveal that Hammer not only outperforms larger models but also demonstrates robust generalization across diverse benchmarks, achieving sota results. Our open source contributions include a specialized dataset for irrelevance detection, a tuning framework for enhanced generalization, and the Hammer models, establishing a new standard for function calling performance.
Key facts. Cited by 55 papers in the map (data through 14 Oct 2026). Placed in Tool learning and function calling, one of 16 directions in LLM agents and tool use. Builds on 19 of its 27 references that are in the map. First posted on arXiv 6 Oct 2024.
Builds on
19 of 27 references.
Closest ancestors · 8
Same direction, newest first
- 2024TinyAgent: Function Calling at the Edge1 Sep
- 2024Granite-Function Calling Model: Introducing Function Calling Abilities via Multi-task Learning of Granular Tasks27 Jun
- 2024APIGen: Automated Pipeline for Generating Verifiable and Diverse Function-Calling Datasets26 Jun
- 2024Seal-Tools: Self-Instruct Tool Learning Dataset for Agent Tuning and Detailed Benchmark14 May
- 2024Octopus: On-device language model for function calling of software APIs2 Apr
- 2024API-BLEND: A Comprehensive Corpora for Training and Benchmarking API LLMs23 Feb
- 2023Gorilla: Large Language Model Connected with Massive APIs24 May
- 2023API-Bank: A Comprehensive Benchmark for Tool-Augmented LLMs14 Apr
Other references · 11
- 2023GPT-4 Technical Reportcited by 18,396
- 2023Direct Preference Optimization: Your Language Model is Secretly a Reward Modelcited by 8,065
- 2023Qwen Technical Reportcited by 3,344
- 2023Retrieval-Augmented Generation for Large Language Models: A Surveycited by 2,212
- 2024Qwen2 Technical Reportcited by 2,120
- 2024τ-bench: A Benchmark for Tool-Agent-User Interaction in Real-World Domainscited by 1,402
- 2022WebShop: Towards Scalable Real-World Web Interaction with Grounded Language Agentscited by 1,251
- 2024DeepSeek-Coder: When the Large Language Model Meets Programming -- The Rise of Code Intelligencecited by 1,181
- 2023An LLM Compiler for Parallel Function Callingcited by 179
- 2024xLAM: A Family of Large Action Models to Empower AI Agent Systemscited by 111
- 2024Reinforcing Language Agents via Policy Optimization with Action Decompositioncited by 16
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Citing papers per year: 2024: 4; 2025: 25; 2026: 26.
55 papers.
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- 2026Harness Engineering in LLM Tool Use via Agent-Native Reusable Tool Primitives1 Sep 2026
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- 2026Attributing Structured-Output Gains in Function Calling: Interface Alignment versus Procedural Transfer1 Jul 2026
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- 2026AutoTool: Automatic Scaling of Tool-Use Capabilities in RL via Decoupled Entropy Constraints7 Mar 2026
- 2026D-CORE: Incentivizing Task Decomposition in Large Reasoning Models for Complex Tool Use2 Feb 2026
- 2026GDPO: Group reward-Decoupled Normalization Policy Optimization for Multi-reward RL Optimization8 Jan 2026
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- 2026Benchmarking LLM Tool-Use in the Wild13 Feb 2026
- 2025Declarative Techniques for NL Queries over Heterogeneous Data18 Oct 2025
- 2025A Survey of Context Engineering for Large Language Models17 Jul 2025
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