diff --git a/Pipfile b/Pipfile
index 08edb5c..fffe94e 100644
--- a/Pipfile
+++ b/Pipfile
@@ -12,6 +12,7 @@ name = "pypi"
 [dev-packages]
 tox = "*"
 pytest = "*"
+mypy = "*"
 build = "*"
 twine = "*"
 setuptools-scm = "~=8.2.0"
diff --git a/TODO b/TODO
index 3ed93ce..acb41d8 100644
--- a/TODO
+++ b/TODO
@@ -140,7 +140,7 @@ Content-Type: application/issue
 ID: 9
 Type: feature
 Title: Type-check the package under mypy strict
-Status: in-progress
+Status: done
 Priority: medium
 Created: 2026-06-17
 Module: sekft
diff --git a/pyproject.toml b/pyproject.toml
index fa22ee5..ae51a61 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -59,6 +59,9 @@ Git = "https://git.code.tiararodney.com/tiararodney/sekft"
 where = ["src"]
 namespaces = true
 
+[tool.setuptools.package-data]
+"tiararodney.sekft" = ["py.typed"]
+
 [tool.pytest.ini_options]
 pythonpath = ["src", "../posix-sdc/src"]
 testpaths = ["tests"]
@@ -70,6 +73,16 @@ markers = [
 
 [tool.mypy]
 strict = true
+mypy_path = "src"
+explicit_package_bases = true
+namespace_packages = true
+
+[[tool.mypy.overrides]]
+module = [
+  "torch.*", "transformers.*", "peft.*", "datasets.*", "bitsandbytes.*",
+  "tiararodney.posix_sdc.*",
+]
+ignore_missing_imports = true
 
 [tool.autopep8]
 max_line_length = 80
diff --git a/src/tiararodney/sekft/eval.py b/src/tiararodney/sekft/eval.py
index 4438134..59f5bfe 100644
--- a/src/tiararodney/sekft/eval.py
+++ b/src/tiararodney/sekft/eval.py
@@ -20,7 +20,9 @@ from __future__ import annotations
 
 import argparse
 import json
+from collections.abc import Callable
 from pathlib import Path
+from typing import Any
 
 from tiararodney.posix_sdc.factory.dashdocker import DashDocker, available
 from tiararodney.posix_sdc.factory.rollout import rollout
@@ -30,7 +32,7 @@ from .sft import normalize_for_template
 
 
 def make_local_operator(base: str, adapter: str, max_new_tokens: int = 64,
-                        temperature: float = 0.7):
+                        temperature: float = 0.7) -> Callable[[list[dict[str, str]]], str]:
     """A ``messages -> command`` callable backed by base + LoRA adapter.
 
     Renders the conversation exactly as the model was trained, appends the
@@ -46,7 +48,7 @@ def make_local_operator(base: str, adapter: str, max_new_tokens: int = 64,
     model = PeftModel.from_pretrained(model, adapter)
     model.eval()
 
-    def operator(messages):
+    def operator(messages: list[dict[str, str]]) -> str:
         msgs = normalize_for_template(messages)
         ids = tok.apply_chat_template(
             msgs, add_generation_prompt=True, return_tensors="pt").to(model.device)
@@ -55,13 +57,14 @@ def make_local_operator(base: str, adapter: str, max_new_tokens: int = 64,
                 ids, max_new_tokens=max_new_tokens,
                 do_sample=temperature > 0, temperature=max(temperature, 1e-2),
                 eos_token_id=tok.eos_token_id, pad_token_id=tok.eos_token_id)
-        return tok.decode(out[0][ids.shape[1]:], skip_special_tokens=True).strip()
+        text: str = tok.decode(out[0][ids.shape[1]:], skip_special_tokens=True).strip()
+        return text
 
     return operator
 
 
 def evaluate(base: str, adapter: str, scenarios_dir: Path, n: int,
-             max_steps: int, temperature: float) -> dict:
+             max_steps: int, temperature: float) -> dict[str, Any]:
     if not available():
         raise SystemExit("sekft-dash image unavailable; `docker build -t sekft-dash .`")
     operator = make_local_operator(base, adapter, temperature=temperature)
diff --git a/src/tiararodney/sekft/py.typed b/src/tiararodney/sekft/py.typed
new file mode 100644
index 0000000..e69de29
diff --git a/src/tiararodney/sekft/resident.py b/src/tiararodney/sekft/resident.py
index c295d48..3b0b8e0 100644
--- a/src/tiararodney/sekft/resident.py
+++ b/src/tiararodney/sekft/resident.py
@@ -23,6 +23,7 @@ import argparse
 import gc
 import json
 from pathlib import Path
+from typing import Any
 
 import torch
 from datasets import Dataset
@@ -68,7 +69,7 @@ class Resident:
 
     # -- build masked rows from kept trajectories --------------------------
 
-    def _rows(self, data_dir: Path, max_len: int) -> list[dict]:
+    def _rows(self, data_dir: Path, max_len: int) -> list[dict[str, list[Any]]]:
         rows = []
         for turns in iter_keepers(data_dir):
             ex = build_masked_example(turns, self.tok)
@@ -83,8 +84,8 @@ class Resident:
     def fit(self, data_dir: str, out: str, lora_r: int = 16, lr: float = 2e-4,
             epochs: float = 3.0, batch: int = 1, accum: int = 8,
             max_len: int = 4096) -> Path:
-        data_dir, out = Path(data_dir).expanduser(), Path(out).expanduser()
-        ds = Dataset.from_list(self._rows(data_dir, max_len))
+        ddir, odir = Path(data_dir).expanduser(), Path(out).expanduser()
+        ds = Dataset.from_list(self._rows(ddir, max_len))
         if not self.load_4bit:
             self.base.gradient_checkpointing_enable()
         model = get_peft_model(self.base, LoraConfig(
@@ -92,31 +93,31 @@ class Resident:
             task_type="CAUSAL_LM", target_modules=LORA_TARGETS))
         model.print_trainable_parameters()
         args = TrainingArguments(
-            output_dir=str(out), per_device_train_batch_size=batch,
+            output_dir=str(odir), per_device_train_batch_size=batch,
             gradient_accumulation_steps=accum, num_train_epochs=epochs,
             learning_rate=lr, fp16=True, logging_steps=1, save_strategy="no",
-            report_to=["tensorboard"], logging_dir=str(out / "runs"),
+            report_to=["tensorboard"], logging_dir=str(odir / "runs"),
             remove_unused_columns=False, warmup_ratio=0.03)
         tr = Trainer(model=model, args=args, train_dataset=ds,
                      data_collator=DataCollatorForSeq2Seq(
                          self.tok, padding=True, label_pad_token_id=-100))
         tr.train()
-        out.mkdir(parents=True, exist_ok=True)
-        model.save_pretrained(str(out))
-        self.tok.save_pretrained(str(out))
-        (out / "log_history.jsonl").write_text(
+        odir.mkdir(parents=True, exist_ok=True)
+        model.save_pretrained(str(odir))
+        self.tok.save_pretrained(str(odir))
+        (odir / "log_history.jsonl").write_text(
             "\n".join(json.dumps(r) for r in tr.state.log_history))
         losses = [h["loss"] for h in tr.state.log_history if "loss" in h]
-        print(f"[resident] fit -> {out}  final loss {losses[-1] if losses else '?'}")
+        print(f"[resident] fit -> {odir}  final loss {losses[-1] if losses else '?'}")
         self.base = model.unload()        # strip LoRA, restore resident base
         del model, tr, ds
         _free()
-        return out
+        return odir
 
     # -- behavioural eval of a saved adapter -------------------------------
 
     def evaluate(self, adapter: str, scenarios_dir: str, n: int = 10,
-                 max_steps: int = 30, temperature: float = 0.7) -> dict:
+                 max_steps: int = 30, temperature: float = 0.7) -> dict[str, Any]:
         from tiararodney.posix_sdc.factory.dashdocker import DashDocker, available
         from tiararodney.posix_sdc.factory.rollout import rollout
         from tiararodney.posix_sdc.schema import Scenario
@@ -130,7 +131,7 @@ class Resident:
             pm = self.base
         pm.eval()
 
-        def operator(messages):
+        def operator(messages: list[dict[str, str]]) -> str:
             msgs = normalize_for_template(messages)
             ids = self.tok.apply_chat_template(
                 msgs, add_generation_prompt=True, return_tensors="pt").to(pm.device)
@@ -139,7 +140,8 @@ class Resident:
                                 temperature=max(temperature, 1e-2),
                                 eos_token_id=self.tok.eos_token_id,
                                 pad_token_id=self.tok.eos_token_id)
-            return self.tok.decode(o[0][ids.shape[1]:], skip_special_tokens=True).strip()
+            text: str = self.tok.decode(o[0][ids.shape[1]:], skip_special_tokens=True).strip()
+            return text
 
         backend = DashDocker()
         rows = []
diff --git a/src/tiararodney/sekft/sft.py b/src/tiararodney/sekft/sft.py
index 5ac8633..0716f69 100644
--- a/src/tiararodney/sekft/sft.py
+++ b/src/tiararodney/sekft/sft.py
@@ -28,9 +28,11 @@ from __future__ import annotations
 
 import argparse
 import json
+from collections.abc import Iterator
 from pathlib import Path
+from typing import Any
 
-def normalize_for_template(messages: list[dict]) -> list[dict]:
+def normalize_for_template(messages: list[dict[str, str]]) -> list[dict[str, str]]:
     """Canonicalise a trajectory for instruct chat templates that have no system
     role and require strict user/assistant alternation (Mistral and friends):
     treat ``system`` as ``user``, then merge consecutive same-role turns by
@@ -42,7 +44,7 @@ def normalize_for_template(messages: list[dict]) -> list[dict]:
     The serving side MUST apply the same canonicalisation, or train and serve
     diverge again.
     """
-    out: list[dict] = []
+    out: list[dict[str, str]] = []
     for m in messages:
         role = "user" if m["role"] == "system" else m["role"]
         if out and out[-1]["role"] == role:
@@ -52,7 +54,7 @@ def normalize_for_template(messages: list[dict]) -> list[dict]:
     return out
 
 
-def build_masked_example(messages: list[dict], tokenizer) -> dict:
+def build_masked_example(messages: list[dict[str, str]], tokenizer: Any) -> dict[str, list[Any]]:
     """Tokenize a trajectory with the tokenizer's OWN chat template and build an
     assistant-only loss mask.
 
@@ -81,7 +83,7 @@ def build_masked_example(messages: list[dict], tokenizer) -> dict:
     return {"input_ids": ids, "attention_mask": [1] * len(ids), "labels": labels}
 
 
-def iter_keepers(data_dir: Path):
+def iter_keepers(data_dir: Path) -> Iterator[list[dict[str, str]]]:
     """Yield ``turns`` (message lists) from trajectory JSONs marked keep."""
     for f in sorted(data_dir.glob("*.json")):
         d = json.loads(f.read_text())
@@ -89,7 +91,7 @@ def iter_keepers(data_dir: Path):
             yield d["turns"]
 
 
-def mask_stats(example: dict) -> tuple[int, int]:
+def mask_stats(example: dict[str, list[Any]]) -> tuple[int, int]:
     """(trained tokens, total tokens) for an example."""
     trained = sum(1 for x in example["labels"] if x != -100)
     return trained, len(example["labels"])
diff --git a/tests/unit/test_sft.py b/tests/unit/test_sft.py
index f2e84b4..d24eef0 100644
--- a/tests/unit/test_sft.py
+++ b/tests/unit/test_sft.py
@@ -15,7 +15,7 @@ class FakeTok:
     """Additive chat template: each turn renders to ``<role> tokens... </e>``;
     the generation prompt appends ``<assistant>``."""
 
-    def apply_chat_template(self, msgs: list[dict], add_generation_prompt: bool = False,
+    def apply_chat_template(self, msgs: list[dict[str, str]], add_generation_prompt: bool = False,
                             return_tensors: Any = None) -> list[str]:
         toks: list[str] = []
         for m in msgs:
@@ -65,7 +65,7 @@ def test_mask_trains_assistant_turns_only() -> None:
 
 def test_mask_raises_on_non_additive_template() -> None:
     class BadTok:
-        def apply_chat_template(self, msgs: list[dict], add_generation_prompt: bool = False,
+        def apply_chat_template(self, msgs: list[dict[str, str]], add_generation_prompt: bool = False,
                                 return_tensors: Any = None) -> list[int]:
             return list(range(len(msgs), 0, -1))   # reversed: prefixes do not nest