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LocalAI enables a cross-request prompt-prefix cache (cache_reuse, see core/config/serving_defaults.go) so repeated prefixes — system prompts, RAG context, agent scaffolds, multi-turn chat — are not reprocessed every turn. For sliding-window-attention (SWA) models (Gemma 2/3, Cohere2, Llama 4, ...) this silently does nothing: llama.cpp defaults to a reduced SWA KV cache sized to the sliding window, and that reduced cache cannot preserve a prompt prefix across requests, so every turn reprocesses the whole prompt anyway. llama.cpp's --swa-full (params.swa_full, already wired through the LocalAI llama.cpp backend's `swa_full` option) keeps the full KV cache so the shared prefix is reused. Enable it automatically, but only for models that are actually SWA: detection reads the gguf-parser-normalized `<arch>.attention.sliding_window` metadata (which also applies llama.cpp's family rules, e.g. Phi-3 → not SWA), right where the GGUF is already parsed for defaults. It is never applied to dense models (pure memory waste) and never overrides an explicit user `swa_full`/`n_swa` choice. Tradeoff: the full SWA cache scales with context_size, so it costs more memory at large contexts — hence the SWA gating and the documented `swa_full:false` opt-out. Assisted-by: Claude:claude-opus-4-8 [Claude Code] golangci-lint Co-authored-by: Ettore Di Giacinto <mudler@localai.io>