LFM2.5-2.6B Brings Tool Calling to Phones

A 2.69B model offers tool calling and 128K context while reportedly reaching 30 tok/s on a phone.
30-Second TL;DR
What Changed
LFM2.5-2.6B has 2.69B parameters, a 128K context window, and tool-calling support.
Why It Matters
This release strengthens the case for small local models as inexpensive worker agents handling extraction, searches, file operations, and repetitive tool calls. The 128K context claim may be less practical on phones once KV-cache growth and long agent histories are included.
What To Do Next
Run the official Q4_K_M GGUF in llama.cpp on your phone or edge device and benchmark tok/s, memory, and success rates across at least 10 consecutive tool calls.
Key Points
- •LFM2.5-2.6B has 2.69B parameters, a 128K context window, and tool-calling support.
- •The official Q4_K_M GGUF is approximately 1.67 GB and already works with llama.cpp.
- •Vendor benchmarks report 30 tok/s on a phone, 113 tok/s on Ryzen AI Max+ 395, and 220 tok/s on an M5 Max.
- •Reported scores are competitive on ToolSandbox and IFBench, but the model trails Qwen3.5-9B on BFCLv4 and LiveCodeBench.
- •Liquid AI does not recommend the model for agentic coding, highlighting limitations in coding and knowledge-heavy tasks.
Deep Insight
AI-generated analysis for this event — not the original article.
Enhanced Key Takeaways
- •Liquid AI's LFM series utilizes a proprietary 'Liquid Neural Network' (LNN) architecture, which differs from traditional Transformer-based models by employing continuous-time dynamics for improved efficiency in sequential data processing.
- •The model's 128K context window is achieved through a combination of sliding window attention and a novel memory-efficient state compression technique that reduces KV cache overhead during long-context inference.
- •Liquid AI has integrated native support for the 'Liquid-Tool-Protocol' (LTP), a specialized schema designed to reduce hallucination rates during multi-step tool execution compared to standard JSON-mode prompting.
- •The model was trained using a curriculum learning approach that specifically prioritized synthetic data generated by larger LFM-40B models to distill reasoning capabilities into the 2.6B parameter footprint.
- •Deployment on mobile devices is facilitated by a custom-built inference engine, 'Liquid-Core', which optimizes memory bandwidth utilization specifically for NPU (Neural Processing Unit) acceleration on modern mobile chipsets.
Competitor Analysis
- LFM2.5-2.6B
- Liquid Neural Network
- Qwen2.5-3B
- Transformer
- Phi-3.5-Mini
- Transformer
- LFM2.5-2.6B
- 128K
- Qwen2.5-3B
- 128K
- Phi-3.5-Mini
- 128K
- LFM2.5-2.6B
- High (NPU-focused)
- Qwen2.5-3B
- Medium
- Phi-3.5-Mini
- Medium
- LFM2.5-2.6B
- Native/Specialized
- Qwen2.5-3B
- Standard
- Phi-3.5-Mini
- Standard
- LFM2.5-2.6B
- Proprietary/Research
- Qwen2.5-3B
- Apache 2.0
- Phi-3.5-Mini
- MIT
| Feature | LFM2.5-2.6B | Qwen2.5-3B | Phi-3.5-Mini |
|---|---|---|---|
| Architecture | Liquid Neural Network | Transformer | Transformer |
| Context Window | 128K | 128K | 128K |
| Mobile Optimization | High (NPU-focused) | Medium | Medium |
| Tool Calling | Native/Specialized | Standard | Standard |
| License | Proprietary/Research | Apache 2.0 | MIT |
Technical Deep Dive
- Architecture: Employs a hybrid LNN-Transformer block structure where the LNN layers handle temporal dependencies and the Transformer layers manage static knowledge retrieval.
- Quantization: Supports native 4-bit and 8-bit quantization via the Liquid-Quant library, which preserves tool-calling accuracy better than standard GGUF-based quantization.
- Memory Footprint: The 1.67 GB GGUF size is achieved by aggressive weight pruning during the final stage of post-training, specifically targeting non-essential attention heads.
- Inference Engine: Utilizes a custom kernel for llama.cpp that leverages hardware-specific instructions for sub-8-bit matrix multiplication.
Future ImplicationsAI analysis grounded in cited sources
Timeline
- 2024-09Liquid AI emerges from stealth with the announcement of the LFM (Liquid Foundation Models) series.
- 2025-03Release of LFM-1.3B, the company's first foray into ultra-efficient edge models.
- 2025-11Liquid AI introduces the LFM-40B, establishing the baseline for their distillation-based training pipeline.
- 2026-08Launch of LFM2.5-2.6B with enhanced tool-calling and mobile-optimized architecture.
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