**Root Cause:** 
Insufficient GPU VRAM to allocate the KV cache for the requested context length. A 262,144-token context requires tens to hundreds of gigabytes of VRAM depending on model size and precision, which vastly exceeds the available ~1 GB of free GPU memory.

**Next Actions:**
1. Reduce the context size by lowering the `--ctx-size` (or `-c`) parameter to a value that fits within available VRAM (e.g., `--ctx-size 8192` or `16384`).
2. If longer context is required, reduce GPU memory pressure by decreasing `--n-gpu-layers` (offloading more model layers to CPU), switching to a more heavily quantized model, or enabling KV cache quantization (`--cache-type-k q8_0 --cache-type-v q8_0`).