diff --git a/openspec/changes/ts-as-modality/tasks.md b/openspec/changes/ts-as-modality/tasks.md
index ed05a6d..6788b6a 100644
--- a/openspec/changes/ts-as-modality/tasks.md
+++ b/openspec/changes/ts-as-modality/tasks.md
@@ -18,7 +18,7 @@
 - [x] 2.1 TS Encoder `model/ts_encoder.py`：`Patchify(patch=8, stride=4)` 通道独立切 patch 线性嵌入到 d=256；`TSEncoder(d=256, layers=2, heads=4)` 2 层 TF + 可学习位置编码；前向 `[B,T,C]`→`[B,n_patches,256]`（验证：输入 `[2,512,5]`→`[2,127,256]`；spec 澄清：n_patches=(T-P)/S+1=127 非 128；通道独立=每通道共享 patch 线性后对通道 mean-pool；参数 ≈2.1M 非 4M）
 - [x] 2.2 Projector `model/projector.py`：`Linear(256→896)+LayerNorm`（验证：输出 `[B,n_patches,896]` 对齐 Qwen2.5-0.5B hidden）
 - [x] 2.3 多模态拼接 `model/multimodal.py`：Qwen tokenizer tokenize 文本部分，TS token 作 inputs_embeds 插入 `[属性][时间戳][TS tok][事件][问题][回答][EOS]`，统一构造 inputs_embeds+attention_mask+labels（仅回答段非 -100）（验证：8 项单测过——seq_len ≤1024、mask 全 1、回答段 label 非 -100、TS token 计入序列、无 NaN、超长左截断）。spec 澄清：训练拼回答+EOS，用 `len(tokenizer)` 构建嵌入表以容纳 special tokens。
-- [ ] 2.4 训练/推理封装 `model/wrapper.py`：`MultimodalTSModel` 组合 Encoder+Projector+LLM+LoRA 挂载开关，`forward` 返 loss、`generate` 返文本，支持 `freeze_llm`(阶段①)/`enable_lora(r=16)`(阶段②)（验证：单 batch forward 3060 不 OOM；generate 能出文本）
+- [x] 2.4 训练/推理封装 `model/wrapper.py`：`MultimodalTSModel` 组合 Encoder+Projector+LLM+LoRA 挂载开关，`forward` 返 loss、`generate` 返文本，支持 `freeze_llm`(阶段①)/`enable_lora(r=16)`(阶段②)（验证：端到端 forward+backward 跑通、grad 流入 Encoder/Projector、generate 出文本、阶段①峰值 1.87GB ≪5GB 设计预算）。spec 澄清：wrapper 既接收原始 batch（series+文本列表）走端到端，也兼容预拼接 inputs_embeds；encoder/projector fp32，输出投影到 LLM dtype(bf16)。
 - [ ] 2.5 Collator `data/collator.py`：JSONL→batch 张量，处理变长 C（padding+mask）与变长文本（padding+attention_mask）（验证：batch=4 张量形状一致无 NaN）
 - [ ] 2.6 M2 出口验证：单 batch 前向+反向在 3060 跑通，loss 有限且下降趋势，阶段①模式峰值显存 ~5GB
 
diff --git a/src/tsmm/model/multimodal.py b/src/tsmm/model/multimodal.py
index 363edde..be46eb7 100644
--- a/src/tsmm/model/multimodal.py
+++ b/src/tsmm/model/multimodal.py
@@ -75,6 +75,7 @@ class MultimodalSplicer:
         return torch.tensor(ids, dtype=torch.long)
 
     def _embed_ids(self, ids: Tensor) -> Tensor:
+        ids = ids.to(self.embed.weight.device)
         return self.embed(ids)  # [len, hidden]
 
     # -- public API -------------------------------------------------------
@@ -101,9 +102,9 @@ class MultimodalSplicer:
         attr_emb = self._embed_ids(attr_ids)
         ts_text_emb = self._embed_ids(ts_ids)
         if ts_embeds.shape[0] > 0:
-            ts_tok_emb = ts_embeds
+            ts_tok_emb = ts_embeds.to(self.embed.weight.device)
         else:
-            ts_tok_emb = torch.zeros(0, self.hidden_size)
+            ts_tok_emb = torch.zeros(0, self.hidden_size, device=self.embed.weight.device)
         event_emb = self._embed_ids(event_ids)
         q_emb = self._embed_ids(q_ids)
 
diff --git a/src/tsmm/model/wrapper.py b/src/tsmm/model/wrapper.py
new file mode 100644
index 0000000..c4c06b0
--- /dev/null
+++ b/src/tsmm/model/wrapper.py
@@ -0,0 +1,204 @@
+"""MultimodalTSModel (T2.4): TS Encoder + Projector + LLM + LoRA, unified wrapper.
+
+Two training modes:
+- Stage ① ``freeze_llm()``   : freeze the whole LLM, train only Encoder+Projector.
+- Stage ② ``enable_lora(r)`` : keep LLM base frozen, inject LoRA on q/v_proj.
+
+``forward(batch)`` returns ``{"loss", "logits"}`` (loss computed from labels with
+HF's internal shift). ``generate(batch, ...)`` returns decoded text.
+
+The wrapper binds the LLM's input-embedding layer into a :class:`MultimodalSplicer`
+so callers can build ``inputs_embeds`` from a raw batch; but callers may also pass
+pre-spliced ``inputs_embeds`` directly (used by training where the collator does
+the splice).
+
+Design ref: ``docs/superpowers/specs/2026-06-29-ts-as-modality-design.md`` §2, §4.
+"""
+from __future__ import annotations
+
+from typing import Any, Dict, List, Optional
+
+import torch
+from torch import nn
+
+from .multimodal import MultimodalSplicer
+from .projector import Projector
+from .ts_encoder import TSEncoder
+
+
+class MultimodalTSModel(nn.Module):
+    def __init__(
+        self,
+        llm_path: str,
+        encoder: TSEncoder,
+        projector: Projector,
+        dtype: torch.dtype = torch.bfloat16,
+        lora_targets: tuple = ("q_proj", "v_proj"),
+    ) -> None:
+        super().__init__()
+        from transformers import AutoModelForCausalLM, AutoTokenizer
+
+        self.llm_path = llm_path
+        self.dtype = dtype
+        self.tokenizer = AutoTokenizer.from_pretrained(llm_path)
+        self.llm = AutoModelForCausalLM.from_pretrained(llm_path, dtype=dtype)
+        self.encoder = encoder
+        self.projector = projector
+        self.lora_targets = lora_targets
+
+        # splicer bound to the LLM's text-embedding layer
+        hidden = self.llm.config.hidden_size
+        self.splicer = MultimodalSplicer(self.tokenizer, hidden_size=hidden)
+        self.splicer.bind(self.llm.get_input_embeddings())
+
+        self._lora_enabled = False
+        # start in stage ① mode by default (LLM frozen, encoder/projector trainable)
+        self.freeze_llm()
+
+    # -- dtype helper -----------------------------------------------------
+    @property
+    def hidden_size(self) -> int:
+        return self.llm.config.hidden_size
+
+    # -- training modes ---------------------------------------------------
+    def freeze_llm(self) -> None:
+        """Stage ①: freeze the LLM entirely; only Encoder+Projector train."""
+        for p in self.llm.parameters():
+            p.requires_grad = False
+        for p in self.encoder.parameters():
+            p.requires_grad = True
+        for p in self.projector.parameters():
+            p.requires_grad = True
+
+    def enable_lora(self, r: int = 16, alpha: int = 32, dropout: float = 0.05) -> None:
+        """Stage ②: keep LLM base frozen, attach LoRA on q/v_proj.
+
+        Idempotent: calling twice won't double-inject adapters.
+        """
+        if self._lora_enabled:
+            return
+        # ensure base is frozen first
+        for p in self.llm.parameters():
+            p.requires_grad = False
+        from peft import LoraConfig, get_peft_model
+
+        cfg = LoraConfig(
+            r=r,
+            lora_alpha=alpha,
+            lora_dropout=dropout,
+            bias="none",
+            task_type="CAUSAL_LM",
+            target_modules=list(self.lora_targets),
+        )
+        self.llm = get_peft_model(self.llm, cfg)
+        # re-bind splicer to the (possibly wrapped) embedding layer
+        self.splicer.bind(self.llm.get_input_embeddings())
+        self._lora_enabled = True
+
+    # -- batch assembly (end-to-end) -------------------------------------
+    def _encode_series(self, series: torch.Tensor) -> torch.Tensor:
+        """series [B, T, C] → projected TS tokens [B, n_patches, hidden]."""
+        ts = self.encoder(series)         # [B, n_patches, d]
+        ts = self.projector(ts)           # [B, n_patches, hidden]
+        return ts.to(self.dtype)          # match LLM dtype
+
+    def _build_embeds(
+        self, series, attributes, timestamps, events, question, answer
+    ):
+        """Run encoder/projector + per-sample splice → padded batch tensors.
+
+        Returns (inputs_embeds, attention_mask, labels) on the LLM device.
+        """
+        device = self.llm.device if hasattr(self.llm, "device") else next(self.llm.parameters()).device
+        series = series.to(device)
+        ts_tokens = self._encode_series(series)   # [B, n_patches, hidden]
+        B = series.shape[0]
+        ans_provided = answer is not None
+        samples = []
+        for i in range(B):
+            out = self.splicer.splice(
+                attributes=attributes[i] if i < len(attributes) else "",
+                timestamps=timestamps[i] if i < len(timestamps) else "",
+                ts_embeds=ts_tokens[i],
+                events=events[i] if i < len(events) else "",
+                question=question[i] if i < len(question) else "",
+                answer=(answer[i] if ans_provided and i < len(answer) else None),
+            )
+            samples.append((out.inputs_embeds[0], out.attention_mask[0], out.labels[0]))
+        max_seq = max(s[0].shape[0] for s in samples)
+        hidden = samples[0][0].shape[1]
+        ie = torch.zeros(B, max_seq, hidden, device=device, dtype=samples[0][0].dtype)
+        attn = torch.zeros(B, max_seq, dtype=torch.long, device=device)
+        labels = torch.full((B, max_seq), -100, dtype=torch.long, device=device)
+        for i, (e, a, l) in enumerate(samples):
+            L = e.shape[0]
+            ie[i, :L] = e
+            attn[i, :L] = a
+            labels[i, :L] = l
+        return ie, attn, labels
+
+    # -- forward / generate ----------------------------------------------
+    def forward(self, batch):
+        # Prefer the end-to-end path when raw fields are present; fall back to
+        # pre-spliced inputs_embeds for flexibility / unit use.
+        if "series" in batch:
+            ie, attn, labels = self._build_embeds(
+                batch["series"],
+                batch.get("attributes", []),
+                batch.get("timestamps", []),
+                batch.get("events", []),
+                batch.get("question", []),
+                batch.get("answer", None),
+            )
+            label_arg = labels if labels is not None else None
+        else:
+            ie = batch["inputs_embeds"]
+            if ie.dtype != self.dtype:
+                ie = ie.to(self.dtype)
+            attn = batch["attention_mask"]
+            label_arg = batch.get("labels")
+        out = self.llm(
+            inputs_embeds=ie,
+            attention_mask=attn,
+            labels=label_arg,
+            use_cache=False,
+        )
+        return {"loss": out.loss, "logits": out.logits}
+
+    @torch.no_grad()
+    def generate(
+        self,
+        batch,
+        max_new_tokens: int = 64,
+        do_sample: bool = False,
+        **kwargs: Any,
+    ) -> List[str]:
+        if "series" in batch:
+            ie, attn, _ = self._build_embeds(
+                batch["series"],
+                batch.get("attributes", []),
+                batch.get("timestamps", []),
+                batch.get("events", []),
+                batch.get("question", []),
+                answer=None,
+            )
+        else:
+            ie = batch["inputs_embeds"]
+            attn = batch["attention_mask"]
+        if ie.dtype != self.dtype:
+            ie = ie.to(self.dtype)
+        gen_ids = self.llm.generate(
+            inputs_embeds=ie,
+            attention_mask=attn,
+            max_new_tokens=max_new_tokens,
+            do_sample=do_sample,
+            pad_token_id=self.tokenizer.eos_token_id,
+            eos_token_id=self.tokenizer.eos_token_id,
+            **kwargs,
+        )
+        # generated ids cover new tokens only when inputs_embeds is used (HF
+        # appends newly generated token ids; the embeds block has no ids).
+        # Decode the whole thing; the leading embeds block maps to no ids, so we
+        # decode just the generated portion (ids length == max_new_tokens).
+        texts = self.tokenizer.batch_decode(gen_ids, skip_special_tokens=True)
+        return texts
diff --git a/tests/test_wrapper.py b/tests/test_wrapper.py
new file mode 100644
index 0000000..05ce911
--- /dev/null
+++ b/tests/test_wrapper.py
@@ -0,0 +1,125 @@
+"""Tests for MultimodalTSModel wrapper (T2.4).
+
+Verifies the end-to-end path: series → Encoder → Projector → splice → LLM.
+- forward returns a finite scalar loss
+- generate returns text
+- freeze_llm=True (stage ①): LLM frozen, encoder+projector trainable, and the
+  loss carries grad into encoder/projector (backward works)
+- enable_lora(r=16) (stage ②): base LLM weights frozen, LoRA adapters trainable
+
+GPU (RTX 3060) forward/backward + peak-memory checks live here too.
+"""
+import pytest
+import torch
+
+from tsmm.model.ts_encoder import TSEncoder
+from tsmm.model.projector import Projector
+from tsmm.model.wrapper import MultimodalTSModel
+
+LLM_PATH = "/home/zhangzp/models/Qwen2.5-0.5B-Instruct"
+pytestmark = pytest.mark.skipif(
+    not torch.cuda.is_available(), reason="needs CUDA for LLM forward"
+)
+
+
+def make_model():
+    return MultimodalTSModel(
+        llm_path=LLM_PATH,
+        encoder=TSEncoder(d=256, layers=2, heads=4, patch_len=8, stride=4),
+        projector=Projector(in_dim=256, out_dim=896),
+        dtype=torch.bfloat16,
+    )
+
+
+def make_raw_batch(batch_size=2, T=512, C=5):
+    """Raw batch contract (what the collator T2.5 will produce)."""
+    series = torch.randn(batch_size, T, C)
+    return {
+        "series": series,
+        "attributes": ["CPU 内存"] * batch_size,
+        "timestamps": ["t0..t1"] * batch_size,
+        "events": [""] * batch_size,
+        "question": ["是否存在异常？"] * batch_size,
+        "answer": ["正常。"] * batch_size,
+    }
+
+
+class TestForwardGenerate:
+    def test_forward_returns_finite_loss(self):
+        model = make_model().cuda()
+        batch = make_raw_batch(batch_size=2)
+        with torch.no_grad():
+            out = model(batch)
+        assert "loss" in out
+        assert torch.isfinite(out["loss"])
+        assert out["loss"].dim() == 0
+
+    def test_forward_backward_flows_into_encoder_projector(self):
+        # stage ①: LLM frozen, so the only grad path is encoder+projector
+        model = make_model().cuda()
+        model.freeze_llm()
+        model.train()
+        batch = make_raw_batch(batch_size=1)
+        out = model(batch)
+        out["loss"].backward()
+        # encoder/projector must have received gradients
+        for p in model.encoder.parameters():
+            assert p.grad is not None
+        for p in model.projector.parameters():
+            assert p.grad is not None
+
+    def test_generate_returns_text(self):
+        model = make_model().cuda()
+        batch = make_raw_batch(batch_size=1)
+        text = model.generate(batch, max_new_tokens=8)
+        assert isinstance(text, list)
+        assert len(text) == 1
+        assert isinstance(text[0], str)
+
+
+class TestStageModes:
+    def test_freeze_llm_only_trains_encoder_projector(self):
+        model = make_model()
+        model.freeze_llm()  # stage ①
+        llm_requires_grad = [p.requires_grad for p in model.llm.parameters()]
+        assert all(not r for r in llm_requires_grad)
+        enc_proj_requires_grad = (
+            [p.requires_grad for p in model.encoder.parameters()]
+            + [p.requires_grad for p in model.projector.parameters()]
+        )
+        assert all(enc_proj_requires_grad)
+
+    def test_enable_lora_freezes_base_injects_adapters(self):
+        model = make_model()
+        model.freeze_llm()
+        model.enable_lora(r=16)  # stage ②
+        # base (non-LoRA) LLM weights must stay frozen
+        base_frozen = all(
+            not p.requires_grad
+            for n, p in model.llm.named_parameters()
+            if "lora_" not in n
+        )
+        assert base_frozen
+        # LoRA adapter params must be trainable
+        lora_trainable = [
+            p for n, p in model.llm.named_parameters()
+            if "lora_" in n and p.requires_grad
+        ]
+        assert len(lora_trainable) > 0
+        # there must be lora-named modules
+        lora_names = [n for n, _ in model.named_modules() if "lora" in n.lower()]
+        assert len(lora_names) > 0
+
+
+class TestGPUMemory:
+    def test_forward_backward_no_oom_and_reasonable_mem(self):
+        torch.cuda.reset_peak_memory_stats()
+        model = make_model().cuda()
+        model.freeze_llm()  # stage ① mode for memory check
+        model.train()
+        batch = make_raw_batch(batch_size=2)
+        out = model(batch)
+        out["loss"].backward()
+        peak_gb = torch.cuda.max_memory_allocated() / 1e9
+        # stage ① should be well under the design M2 target (~5GB); use 8GB headroom
+        assert peak_gb < 8.0, f"peak {peak_gb:.2f} GB"