Agent wrappers lag llama.cpp web UI

This is less a llama.cpp performance problem than an agent-stack tax: raw local inference can feel fast, but agent UX often adds a lot of work before decoding starts.

• –llama-server's built-in web UI is close to a direct completion path, so time-to-first-token stays low
• –Agent tools often add system prompts, repo/context loading, tool selection, JSON formatting, and retry logic before they stream anything
• –Large context windows and prompt-processing time can dominate latency even when token generation itself is fast
• –If the same local backend sits underneath both tools, benchmarking prompt evaluation separately from decode speed usually reveals where the slowdown lives
• –Practical fixes usually involve shrinking preflight context, reducing tool steps, and tuning server-side settings like parallelism or speculative decoding