diff --git a/scripts/frank-default-small.env b/scripts/frank-default-small.env
index e5efc30..5ad2769 100644
--- a/scripts/frank-default-small.env
+++ b/scripts/frank-default-small.env
@@ -39,6 +39,13 @@ NGRAM_LOOKUP_MAX=5
 NGRAM_LOOKUP_MIN=1
 NUM_SPEC_TOKENS=5
 
+# Tool calling. Clients (pi, OpenWebUI) send tool_choice=auto; without
+# --enable-auto-tool-choice vLLM rejects it with HTTP 400. The Avesed
+# chat template renders tools in the Qwen3 XML format, so the qwen3_xml
+# parser is the matching one.
+ENABLE_AUTO_TOOL_CHOICE=1
+TOOL_CALL_PARSER=qwen3_xml
+
 # RDNA flash-attention for the vision encoder (and general FA paths).
 # Without this, the mm encoder falls back to torch SDPA and the warmup
 # OOMs (256 GiB score matrix at max_model_len; measured 2026-08-17).
diff --git a/scripts/serve-frank-small.sh b/scripts/serve-frank-small.sh
index 48472a7..150e72f 100755
--- a/scripts/serve-frank-small.sh
+++ b/scripts/serve-frank-small.sh
@@ -33,12 +33,20 @@ fi
 : "${NGRAM_LOOKUP_MAX:=5}"
 : "${NGRAM_LOOKUP_MIN:=1}"
 : "${NUM_SPEC_TOKENS:=5}"
+: "${ENABLE_AUTO_TOOL_CHOICE:=1}"
+: "${TOOL_CALL_PARSER:=qwen3_xml}"
 
 if [[ ! -x "$VLLM_BIN" ]]; then
     echo "missing vllm binary: $VLLM_BIN" >&2
     exit 1
 fi
 
+TOOL_ARGS=()
+if [[ "${ENABLE_AUTO_TOOL_CHOICE}" == "1" ]]; then
+    TOOL_ARGS+=(--enable-auto-tool-choice)
+    TOOL_ARGS+=(--tool-call-parser "${TOOL_CALL_PARSER}")
+fi
+
 exec "$VLLM_BIN" serve "$MODEL" \
     --host "$BIND_ADDR" \
     --port "$LISTEN_PORT" \
@@ -50,4 +58,5 @@ exec "$VLLM_BIN" serve "$MODEL" \
     --gpu-memory-utilization "$GPU_MEMORY_UTILIZATION" \
     --speculative-config "{\"method\":\"ngram\",\"prompt_lookup_max\":$NGRAM_LOOKUP_MAX,\"prompt_lookup_min\":$NGRAM_LOOKUP_MIN,\"num_speculative_tokens\":$NUM_SPEC_TOKENS}" \
     --reasoning-parser qwen3 \
-    --trust-remote-code
+    --trust-remote-code \
+    "${TOOL_ARGS[@]}"