Needle 2 - The 14 MB Agentic LLM for Tiny Devices | Cactus

Count budget phones, Raspberry Pis, microcontrollers, wearables, small robots like Reachy Mini, and connected home devices, and roughly four in five edge devices cost under $200. That is the hardware Needle targets: no GPU, no NPU, a few hundred MB of RAM.Function Call & Device Use: Turning on a light does not need a frontier model. A watch, a home, a robot: each already exposes its abilities as functions with typed parameters, so the only hard part is mapping a messy sentence onto them: which function, with which values. Framed that way, the problem needs no world knowledge and no open-ended prose, which is why 45M parameters suffice where chat needs billions. That smaller formulation is the bet everything else follows from.Extraction & Structured Outputs: The schema is the interface, and the same formulation covers documents: a schema plus a paragraph returns typed fields, an enum field is a classifier, an array field collects a list in one call. We enforce this with a contract, not a convention: every turn is answered with a call envelope, the empty call is the refusal, and a byte-level grammar compiled from the declared schemas constrains every token. The grammar carries the syntax, so all 45M parameters go to choosing functions and grounding arguments in the user's words.Edge-Cloud Collaboration: No small model covers everything, so Needle says so instead of guessing: every response carries a learned confidence score, and off-topic requests return the empty call. Above your threshold, act; below it, re-ask or escalate to the cloud. Most device requests are routine control, so escalation stays rare and the default path stays private, instant, and free.Lossless 2bit Quantization: Small models break under post-hoc quantization, so we never quantize post-hoc: Needle 2 trains against Cactus Quants from pretrain through post-train, weights, activations, and KV cache alike. The 2bit model you deploy is the model that was trained. That is what fits 45M parameters into 14MB with nothing lost on our battery.Co-designed Model & Inference: Every architectural choice was benchmarked on the target hardware before it earned its parameters, and the deliverable is the pair, not the weights: a single dependency-free C++ binary that probes the CPU at startup and picks its kernels, with the model, tokenizer, and grammar compiler sealed inside. One artifact runs from Cortex-M to x86 to WebAssembly. There is nothing to install and nothing to download.Fine-tune on your Mac/PC: Every product has its own tool vocabulary, and a 45M model is small enough to retrain where it runs: the repo and python package tune and test on your own computer in minutes to a few hours.