diff --git a/scripts/definition_smoke.py b/scripts/definition_smoke.py
new file mode 100644
index 0000000..97d4c42
--- /dev/null
+++ b/scripts/definition_smoke.py
@@ -0,0 +1,354 @@
+"""Smoke test engine definitions on a deployed Lilo control plane.
+
+For each definition this creates a training client, runs a cross-entropy step,
+publishes the weights and samples from them, then runs an importance-sampling
+step on the sampled response and samples once more. The model is unloaded
+afterwards so the trainer is released.
+
+Usage::
+
+    export TINKER_BASE_URL=https://...modal.run
+    export TINKER_API_KEY=tml-lilo-...
+    uv run scripts/definition_smoke.py                  # default definition
+    uv run scripts/definition_smoke.py --list           # show all definitions
+    uv run scripts/definition_smoke.py --parallel \
+        --definition-id qwen3_5_9b_miles_lora_16k \
+        --definition-id qwen3_5_4b_full_64k
+
+Any id from ``lilo.providers.modal.definitions`` works; the client type
+(full or LoRA) and the LoRA target flags are read from the definition module so
+the request matches what the deployment accepts. The definition id is passed as
+``base_model`` so non-cataloged definitions can be targeted directly.
+Definitions run sequentially unless ``--parallel`` is set.
+"""
+
+from __future__ import annotations
+
+import argparse
+import json
+import math
+import os
+import time
+import traceback
+from concurrent.futures import ThreadPoolExecutor
+from pathlib import Path
+from typing import Any
+
+import httpx
+import tinker
+from tinker import types
+
+from lilo.backends.miles_config import lora_target_flags
+from lilo.client import create_full_training_client
+from lilo.providers.modal.app import DEFINITIONS, module_for
+
+DEFAULT_DEFINITION = "qwen3_8_27b_miles_lora_64k"
+TIMEOUT = 60 * 60
+PROMPT = "Question: What is two plus two?\nAnswer:"
+
+
+def _finite_metrics(metrics: dict[str, Any]) -> dict[str, float]:
+    numeric = {
+        key: float(value)
+        for key, value in metrics.items()
+        if isinstance(value, int | float)
+    }
+    if not numeric or any(not math.isfinite(value) for value in numeric.values()):
+        raise RuntimeError(f"non-finite metrics: {metrics}")
+    return numeric
+
+
+def _sft_datum(tokenizer) -> types.Datum:
+    prompt = tokenizer.encode(PROMPT, add_special_tokens=True)
+    completion = tokenizer.encode(" 4", add_special_tokens=False)
+    tokens = prompt + completion
+    return types.Datum(
+        model_input=types.ModelInput.from_ints(tokens[:-1]),
+        loss_fn_inputs={
+            "target_tokens": tokens[1:],
+            "weights": [0.0] * (len(prompt) - 1) + [1.0] * len(completion),
+        },
+    )
+
+
+def _rl_datum(
+    prompt: list[int],
+    response: list[int],
+    logprobs: list[float],
+    reward: float,
+) -> types.Datum:
+    prompt_targets = len(prompt) - 1
+    return types.Datum(
+        model_input=types.ModelInput.from_ints(prompt + response[:-1]),
+        loss_fn_inputs={
+            "target_tokens": prompt[1:] + response,
+            "logprobs": [0.0] * prompt_targets + logprobs,
+            "advantages": [0.0] * prompt_targets + [reward] * len(response),
+        },
+    )
+
+
+def _step(training, data: list[types.Datum], loss_fn: str, lr: float) -> dict:
+    started = time.perf_counter()
+    forward_result = training.forward_backward(data, loss_fn).result(timeout=TIMEOUT)
+    forward_done = time.perf_counter()
+    if len(forward_result.loss_fn_outputs) != len(data):
+        raise RuntimeError(
+            f"expected {len(data)} loss outputs, got "
+            f"{len(forward_result.loss_fn_outputs)}"
+        )
+    optimizer_result = training.optim_step(types.AdamParams(learning_rate=lr)).result(
+        timeout=TIMEOUT
+    )
+    finished = time.perf_counter()
+    optimizer_metrics = _finite_metrics(optimizer_result.metrics)
+    if optimizer_metrics.get("update_successful:mean") != 1.0:
+        raise RuntimeError(f"optimizer step skipped the update: {optimizer_metrics}")
+    return {
+        "loss_fn": loss_fn,
+        "metrics": _finite_metrics(forward_result.metrics),
+        "optimizer_metrics": optimizer_metrics,
+        "forward_backward_seconds": forward_done - started,
+        "optimizer_seconds": finished - forward_done,
+    }
+
+
+def _publish_and_sample(
+    training, tokenizer, prompt: list[int], max_tokens: int
+) -> tuple[dict, list[int], list[float]]:
+    started = time.perf_counter()
+    sampling = training.save_weights_and_get_sampling_client()
+    published = time.perf_counter()
+    result = sampling.sample(
+        prompt=types.ModelInput.from_ints(prompt),
+        num_samples=1,
+        sampling_params=types.SamplingParams(max_tokens=max_tokens, temperature=1.0),
+    ).result(timeout=TIMEOUT)
+    finished = time.perf_counter()
+    if len(result.sequences) != 1:
+        raise RuntimeError(f"expected one sequence, got {len(result.sequences)}")
+    sequence = result.sequences[0]
+    tokens = list(sequence.tokens)
+    logprobs = [float(value) for value in sequence.logprobs or ()]
+    if not tokens or len(logprobs) != len(tokens):
+        raise RuntimeError("sample did not return matching tokens and logprobs")
+    if any(not math.isfinite(value) for value in logprobs):
+        raise RuntimeError(f"non-finite sample logprobs: {logprobs}")
+    text = tokenizer.decode(tokens)
+    return (
+        {
+            "publish_seconds": published - started,
+            "sample_seconds": finished - published,
+            "output_tokens": len(tokens),
+            "text": text,
+        },
+        tokens,
+        logprobs,
+    )
+
+
+def _unload(base_url: str, api_key: str, model_id: str) -> None:
+    headers = {"X-API-Key": api_key}
+    with httpx.Client(base_url=base_url, headers=headers, timeout=60) as client:
+        response = client.post("/api/v1/unload_model", json={"model_id": model_id})
+        if response.status_code == 404:
+            return
+        response.raise_for_status()
+        request_id = response.json()["request_id"]
+        while True:
+            response = client.post(
+                "/api/v1/retrieve_future", json={"request_id": request_id}
+            )
+            if response.status_code != 408:
+                response.raise_for_status()
+                return
+            time.sleep(1)
+
+
+def _create_training_client(
+    service: tinker.ServiceClient, definition: Any, rank: int | None
+) -> tuple[tinker.TrainingClient, dict[str, Any]]:
+    definition_id = definition.DEFINITION_ID
+    if definition.PARAMETERIZATION == "full":
+        training = create_full_training_client(service, definition_id)
+        return training, {"parameterization": "full"}
+    train_attn, train_mlp, train_unembed = lora_target_flags(definition.TARGET_MODULES)
+    if rank is None:
+        rank = min(16, definition.MAX_LORA_RANK)
+    training = service.create_lora_training_client(
+        base_model=definition_id,
+        rank=rank,
+        train_attn=train_attn,
+        train_mlp=train_mlp,
+        train_unembed=train_unembed,
+    )
+    return training, {
+        "parameterization": "lora",
+        "rank": rank,
+        "train_attn": train_attn,
+        "train_mlp": train_mlp,
+        "train_unembed": train_unembed,
+    }
+
+
+def _run_definition(
+    definition_id: str,
+    *,
+    base_url: str,
+    api_key: str,
+    rank: int | None,
+    max_tokens: int,
+) -> dict:
+    report: dict[str, Any] = {
+        "definition_id": definition_id,
+        "status": "running",
+        "started_at": time.time(),
+        "phases": {},
+    }
+    training = None
+    try:
+        definition = module_for(definition_id)
+        service = tinker.ServiceClient(base_url=base_url, api_key=api_key)
+        started = time.perf_counter()
+        training, spec = _create_training_client(service, definition, rank)
+        info = training.get_info()
+        if info.is_lora != (spec["parameterization"] == "lora"):
+            raise RuntimeError(f"expected {spec['parameterization']} model, got {info}")
+        tokenizer = training.get_tokenizer()
+        report["phases"]["provision"] = {
+            "seconds": time.perf_counter() - started,
+            "model_id": str(training.model_id),
+            "base_model": info.model_name,
+            "lora_rank": info.lora_rank,
+            **spec,
+        }
+        print(json.dumps({"definition": definition_id, **report["phases"]}))
+
+        report["phases"]["sft_step"] = _step(
+            training, [_sft_datum(tokenizer)], "cross_entropy", 1e-4
+        )
+        print(json.dumps({"definition": definition_id, "sft_step": "ok"}))
+
+        prompt = tokenizer.encode(PROMPT, add_special_tokens=True)
+        sample, tokens, logprobs = _publish_and_sample(
+            training, tokenizer, prompt, max_tokens
+        )
+        report["phases"]["sample_1"] = sample
+        print(json.dumps({"definition": definition_id, "sample_1": sample["text"]}))
+
+        reward = 1.0 if "4" in sample["text"] else -1.0
+        report["phases"]["rl_step"] = _step(
+            training,
+            [_rl_datum(prompt, tokens, logprobs, reward)],
+            "importance_sampling",
+            1e-5,
+        )
+        report["phases"]["rl_step"]["reward"] = reward
+        print(json.dumps({"definition": definition_id, "rl_step": "ok"}))
+
+        sample, _, _ = _publish_and_sample(training, tokenizer, prompt, max_tokens)
+        report["phases"]["sample_2"] = sample
+        print(json.dumps({"definition": definition_id, "sample_2": sample["text"]}))
+
+        report["status"] = "passed"
+    except Exception as exc:  # noqa: BLE001 - report every failure per definition
+        report["status"] = "failed"
+        report["error"] = f"{type(exc).__name__}: {exc}"
+        report["traceback"] = traceback.format_exc()
+    finally:
+        report["finished_at"] = time.time()
+        report["elapsed_seconds"] = report["finished_at"] - report["started_at"]
+        if training is not None:
+            try:
+                _unload(base_url, api_key, str(training.model_id))
+                report["cleanup"] = {"model_unloaded": True}
+            except (httpx.HTTPError, RuntimeError, TimeoutError, ValueError) as exc:
+                error = f"{type(exc).__name__}: {exc}"
+                report["cleanup"] = {"model_unloaded": False, "error": error}
+                report["status"] = "failed"
+                report.setdefault("error", f"cleanup failed: {error}")
+    return report
+
+
+def main() -> None:
+    parser = argparse.ArgumentParser(description=__doc__.split("\n\n")[0])
+    known = [definition.DEFINITION_ID for definition in DEFINITIONS]
+    parser.add_argument(
+        "--definition-id",
+        action="append",
+        dest="definition_ids",
+        choices=known,
+        metavar="ID",
+        help=f"engine definition id (repeatable); default {DEFAULT_DEFINITION}",
+    )
+    parser.add_argument(
+        "--list", action="store_true", help="print known definitions and exit"
+    )
+    parser.add_argument("--base-url", default=os.environ.get("TINKER_BASE_URL"))
+    parser.add_argument(
+        "--rank",
+        type=int,
+        help="LoRA rank; default min(16, definition MAX_LORA_RANK)",
+    )
+    parser.add_argument("--max-tokens", type=int, default=32)
+    parser.add_argument("--parallel", action="store_true")
+    parser.add_argument(
+        "--output",
+        type=Path,
+        default=Path("scripts/results/definition_smoke.json"),
+    )
+    args = parser.parse_args()
+    if args.list:
+        for definition in DEFINITIONS:
+            print(
+                f"{definition.DEFINITION_ID:40} {definition.PARAMETERIZATION:5} "
+                f"{definition.GPUS}x{definition.GPU_TYPE} "
+                f"ctx={definition.MAX_CONTEXT_LENGTH}"
+                + ("" if definition.CATALOG_VISIBLE else "  (not cataloged)")
+            )
+        return
+    if not args.base_url:
+        parser.error("--base-url or TINKER_BASE_URL is required")
+    api_key = os.environ.get("TINKER_API_KEY")
+    if not api_key:
+        parser.error("TINKER_API_KEY is required")
+    definition_ids = args.definition_ids or [DEFAULT_DEFINITION]
+
+    def run(definition_id: str) -> dict:
+        return _run_definition(
+            definition_id,
+            base_url=args.base_url,
+            api_key=api_key,
+            rank=args.rank,
+            max_tokens=args.max_tokens,
+        )
+
+    if args.parallel:
+        with ThreadPoolExecutor(max_workers=len(definition_ids)) as pool:
+            reports = list(pool.map(run, definition_ids))
+    else:
+        reports = [run(definition_id) for definition_id in definition_ids]
+
+    stamp = f"{time.strftime('%Y%m%d%H%M%S')}.{os.getpid()}"
+    output = args.output.with_name(f"{args.output.stem}.{stamp}{args.output.suffix}")
+    output.parent.mkdir(parents=True, exist_ok=True)
+    output.write_text(
+        json.dumps({"base_url": args.base_url, "results": reports}, indent=2) + "\n",
+        encoding="utf-8",
+    )
+    for report in reports:
+        line = {
+            "definition": report["definition_id"],
+            "status": report["status"],
+            "elapsed_seconds": round(report["elapsed_seconds"], 1),
+        }
+        if report["status"] != "passed":
+            line["error"] = report.get("error")
+        print(json.dumps(line))
+    print(output)
+    if any(report["status"] != "passed" for report in reports):
+        raise SystemExit(1)
+
+
+if __name__ == "__main__":
+    main()
diff --git a/src/lilo/backends/miles_config.py b/src/lilo/backends/miles_config.py
index ee90897..cf108af 100644
--- a/src/lilo/backends/miles_config.py
+++ b/src/lilo/backends/miles_config.py
@@ -18,6 +18,23 @@
     "linear_fc2": ("down_proj",),
     "output_layer": ("lm_head",),
 }
+_ATTN_LEAVES = frozenset(
+    {"linear_qkv", "linear_q", "linear_k", "linear_v", "linear_proj"}
+)
+_MLP_LEAVES = frozenset(
+    {"linear_fc1", "linear_fc1_gate", "linear_fc1_up", "linear_fc2"}
+)
+_UNEMBED_LEAVES = frozenset({"output_layer"})
+
+
+def lora_target_flags(target_modules: tuple[str, ...]) -> tuple[bool, bool, bool]:
+    """Return ``(train_attn, train_mlp, train_unembed)`` implied by target modules."""
+    leaves = {module.rsplit(".", 1)[-1] for module in target_modules}
+    return (
+        bool(leaves & _ATTN_LEAVES),
+        bool(leaves & _MLP_LEAVES),
+        bool(leaves & _UNEMBED_LEAVES),
+    )
 
 
 @dataclass(frozen=True, slots=True)
diff --git a/src/lilo/backends/miles_lora.py b/src/lilo/backends/miles_lora.py
index 2e88f30..6a59f83 100644
--- a/src/lilo/backends/miles_lora.py
+++ b/src/lilo/backends/miles_lora.py
@@ -25,7 +25,11 @@
     ModelSpec,
     SamplerPublication,
 )
-from .miles_config import MilesBackendConfig, parse_backend_config
+from .miles_config import (
+    MilesBackendConfig,
+    lora_target_flags,
+    parse_backend_config,
+)
 from .miles_runtime.data import build_outputs, pad_slot_rows, prepare_batch
 from .miles_runtime.profiling import RankProfiler, StepPhaseTimer, TorchProfileConfig
 from .miles_runtime.runtime import MilesRuntime
@@ -552,18 +556,7 @@ def _validate_job(self, state: MilesJobState) -> None:
             )
         if state.seed is not None:
             raise ValueError("Miles multi-LoRA does not support per-model seeds")
-        leaves = {module.rsplit(".", 1)[-1] for module in self.config.target_modules}
-        configured = (
-            bool(
-                leaves
-                & {"linear_qkv", "linear_q", "linear_k", "linear_v", "linear_proj"}
-            ),
-            bool(
-                leaves
-                & {"linear_fc1", "linear_fc1_gate", "linear_fc1_up", "linear_fc2"}
-            ),
-            bool(leaves & {"output_layer"}),
-        )
+        configured = lora_target_flags(self.config.target_modules)
         requested = (state.train_attn, state.train_mlp, state.train_unembed)
         if requested != configured:
             raise ValueError(