MLX server: prompt cache limit (memory); restart after the T01 test

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014aUaQeLnwbb1zTpN7kHeat

train/serve.sh

@@ -1,11 +1,13 @@
 #!/bin/sh
 # Serve the base model (no adapter) with mlx_lm.server. Settings: train/README.md.
 # Usage: train/serve.sh [--adapter-path PATH]
+# Prompt cache limit: without it the cache grew to 7.9 GB in 15 min (2026-10-03); A4H needs 22 GB.
 cd "$(dirname "$0")/.."
 exec train/.venv/bin/mlx_lm.server \
   --model "$HOME/models/Qwen3.8-27B-4bit" \
   --host 127.0.0.1 --port 8080 \
   --temp 0.2 --top-p 0.95 --top-k 20 --min-p 0 \
   --max-tokens 32768 \
+  --prompt-cache-size 4 --prompt-cache-bytes 6000000000 \
   --chat-template-args '{"enable_thinking": true, "reasoning_effort": "medium"}' \
   "$@"