diff --git a/examples/ablation/run_agent_loop_benchmarks.py b/examples/ablation/run_agent_loop_benchmarks.py
index 6c75ac0..4add631 100644
--- a/examples/ablation/run_agent_loop_benchmarks.py
+++ b/examples/ablation/run_agent_loop_benchmarks.py
@@ -29,6 +29,12 @@
 REPO_ROOT = Path(__file__).resolve().parents[2]
 OUT_DIR = Path(__file__).parent / "diagnostics"
 DEFAULT_MSMARCO_PATH = REPO_ROOT / "tests" / "benchmark" / "data" / "msmarco_passage.json"
+DEFAULT_LLM_BASE_URL = "http://localhost:8012/v1"
+DEFAULT_LLM_MODEL = "Qwen3.6-27B"
+DEFAULT_API_KEY_ENV = "OPENAI_API_KEY"
+DEEPSEEK_LLM_BASE_URL = "https://api.deepseek.com/v1"
+DEEPSEEK_LLM_MODEL = "deepseek-v4-flash"
+DEEPSEEK_API_KEY_ENV = "DEEPSEEK_API_KEY"
 
 _AGENT_LOOP_EXTRA_CONTEXT = """Benchmark context:
 - You are evaluating retrieval, not general knowledge.
@@ -66,6 +72,27 @@ def _load_local_env(paths: list[Path] | None = None) -> None:
             os.environ[key] = value.strip().strip("\"'")
 
 
+def _resolve_llm_settings(
+    *,
+    preset: str,
+    llm_base_url: str | None,
+    model: str | None,
+    api_key_env: str | None,
+) -> tuple[str, str, str]:
+    """Resolve provider defaults while preserving explicit CLI overrides."""
+    if preset == "deepseek":
+        return (
+            llm_base_url or DEEPSEEK_LLM_BASE_URL,
+            model or DEEPSEEK_LLM_MODEL,
+            api_key_env or DEEPSEEK_API_KEY_ENV,
+        )
+    return (
+        llm_base_url or DEFAULT_LLM_BASE_URL,
+        model or DEFAULT_LLM_MODEL,
+        api_key_env or DEFAULT_API_KEY_ENV,
+    )
+
+
 @dataclass(slots=True)
 class AgentLoopRow:
     qid: str
@@ -493,9 +520,18 @@ async def amain(argv: list[str] | None = None) -> int:
     parser.add_argument("--sqlite-db-path", type=Path, required=True)
     parser.add_argument("--subset", type=int, default=20)
     parser.add_argument("--corpus-limit", type=int, default=0)
-    parser.add_argument("--llm-base-url", default="http://localhost:8012/v1")
-    parser.add_argument("--model", default="Qwen3.6-27B")
-    parser.add_argument("--api-key-env", default="OPENAI_API_KEY")
+    parser.add_argument(
+        "--llm-preset",
+        choices=("local", "deepseek"),
+        default="local",
+        help=(
+            "Provider preset for omitted LLM settings. "
+            "deepseek => api.deepseek.com/v1, deepseek-v4-flash, DEEPSEEK_API_KEY."
+        ),
+    )
+    parser.add_argument("--llm-base-url", default=None)
+    parser.add_argument("--model", default=None)
+    parser.add_argument("--api-key-env", default=None)
     parser.add_argument("--max-turns", type=int, default=5)
     parser.add_argument(
         "--llm-timeout",
@@ -543,6 +579,12 @@ async def amain(argv: list[str] | None = None) -> int:
         raise SystemExit("--preflight-timeout must be positive")
     if args.resume and args.out_jsonl is None:
         raise SystemExit("--resume requires --out-jsonl")
+    args.llm_base_url, args.model, args.api_key_env = _resolve_llm_settings(
+        preset=args.llm_preset,
+        llm_base_url=args.llm_base_url,
+        model=args.model,
+        api_key_env=args.api_key_env,
+    )
     if not args.msmarco_path.exists():
         raise SystemExit(f"{args.msmarco_path} does not exist")
     if not args.sqlite_db_path.exists():
diff --git a/tests/test_agent_search_benchmarks.py b/tests/test_agent_search_benchmarks.py
index bdaef45..02d39f6 100644
--- a/tests/test_agent_search_benchmarks.py
+++ b/tests/test_agent_search_benchmarks.py
@@ -173,6 +173,45 @@ def test_agent_loop_load_local_env_without_overriding_shell_env(
     assert os.environ["DEEPSEEK_API_KEY"] == "from_shell"
 
 
+def test_agent_loop_deepseek_preset_resolves_provider_defaults() -> None:
+    assert loop_runner._resolve_llm_settings(
+        preset="deepseek",
+        llm_base_url=None,
+        model=None,
+        api_key_env=None,
+    ) == (
+        "https://api.deepseek.com/v1",
+        "deepseek-v4-flash",
+        "DEEPSEEK_API_KEY",
+    )
+
+
+def test_agent_loop_llm_preset_preserves_explicit_overrides() -> None:
+    assert loop_runner._resolve_llm_settings(
+        preset="deepseek",
+        llm_base_url="https://example.test/v1",
+        model="custom-model",
+        api_key_env="CUSTOM_KEY",
+    ) == (
+        "https://example.test/v1",
+        "custom-model",
+        "CUSTOM_KEY",
+    )
+
+
+def test_agent_loop_local_preset_keeps_existing_defaults() -> None:
+    assert loop_runner._resolve_llm_settings(
+        preset="local",
+        llm_base_url=None,
+        model=None,
+        api_key_env=None,
+    ) == (
+        "http://localhost:8012/v1",
+        "Qwen3.6-27B",
+        "OPENAI_API_KEY",
+    )
+
+
 def test_llm_preflight_error_message_names_endpoint_and_skip_hint() -> None:
     msg = loop_runner._llm_preflight_error_message(
         "http://127.0.0.1:18012/v1",