diff --git a/skills/python-type-safety/SKILL.md b/skills/python-type-safety/SKILL.md
new file mode 100644
index 0000000..cce2377
--- /dev/null
+++ b/skills/python-type-safety/SKILL.md
@@ -0,0 +1,200 @@
+---
+name: python-type-safety
+description: Python type safety with type hints, generics, protocols, and strict type checking. Use when adding type annotations, implementing generic classes, defining structural interfaces, or configuring mypy/pyright.
+---
+
+# Python Type Safety
+
+Leverage Python's type system to catch errors at static analysis time. Type annotations serve as enforced documentation that tooling validates automatically.
+
+## When to Use This Skill
+
+- Adding type hints to existing code
+- Creating generic, reusable classes
+- Defining structural interfaces with protocols
+- Configuring mypy or pyright for strict checking
+- Understanding type narrowing and guards
+- Building type-safe APIs and libraries
+
+## Core Concepts
+
+### 1. Type Annotations
+
+Declare expected types for function parameters, return values, and variables.
+
+### 2. Generics
+
+Write reusable code that preserves type information across different types.
+
+### 3. Protocols
+
+Define structural interfaces without inheritance (duck typing with type safety).
+
+### 4. Type Narrowing
+
+Use guards and conditionals to narrow types within code blocks.
+
+## Quick Start
+
+```python
+def get_user(user_id: str) -> User | None:
+    """Return type makes 'might not exist' explicit."""
+    ...
+
+# Type checker enforces handling None case
+user = get_user("123")
+if user is None:
+    raise UserNotFoundError("123")
+print(user.name)  # Type checker knows user is User here
+```
+
+## Fundamental Patterns
+
+### Pattern 1: Annotate All Public Signatures
+
+Every public function, method, and class should have type annotations.
+
+```python
+def get_user(user_id: str) -> User:
+    """Retrieve user by ID."""
+    ...
+
+def process_batch(
+    items: list[Item],
+    max_workers: int = 4,
+) -> BatchResult[ProcessedItem]:
+    """Process items concurrently."""
+    ...
+
+class UserRepository:
+    def __init__(self, db: Database) -> None:
+        self._db = db
+
+    async def find_by_id(self, user_id: str) -> User | None:
+        """Return User if found, None otherwise."""
+        ...
+
+    async def find_by_email(self, email: str) -> User | None:
+        ...
+
+    async def save(self, user: User) -> User:
+        """Save and return user with generated ID."""
+        ...
+```
+
+Use `mypy --strict` or `pyright` in CI to catch type errors early. For existing projects, enable strict mode incrementally using per-module overrides.
+
+### Pattern 2: Use Modern Union Syntax
+
+Python 3.10+ provides cleaner union syntax.
+
+```python
+# Preferred (3.10+)
+def find_user(user_id: str) -> User | None:
+    ...
+
+def parse_value(v: str) -> int | float | str:
+    ...
+
+# Older style (still valid, needed for 3.9)
+from typing import Optional, Union
+
+def find_user(user_id: str) -> Optional[User]:
+    ...
+```
+
+### Pattern 3: Type Narrowing with Guards
+
+Use conditionals to narrow types for the type checker.
+
+```python
+def process_user(user_id: str) -> UserData:
+    user = find_user(user_id)
+
+    if user is None:
+        raise UserNotFoundError(f"User {user_id} not found")
+
+    # Type checker knows user is User here, not User | None
+    return UserData(
+        name=user.name,
+        email=user.email,
+    )
+
+def process_items(items: list[Item | None]) -> list[ProcessedItem]:
+    # Filter and narrow types
+    valid_items = [item for item in items if item is not None]
+    # valid_items is now list[Item]
+    return [process(item) for item in valid_items]
+```
+
+### Pattern 4: Generic Classes
+
+Create type-safe reusable containers.
+
+```python
+from typing import TypeVar, Generic
+
+T = TypeVar("T")
+E = TypeVar("E", bound=Exception)
+
+class Result(Generic[T, E]):
+    """Represents either a success value or an error."""
+
+    def __init__(
+        self,
+        value: T | None = None,
+        error: E | None = None,
+    ) -> None:
+        if (value is None) == (error is None):
+            raise ValueError("Exactly one of value or error must be set")
+        self._value = value
+        self._error = error
+
+    @property
+    def is_success(self) -> bool:
+        return self._error is None
+
+    @property
+    def is_failure(self) -> bool:
+        return self._error is not None
+
+    def unwrap(self) -> T:
+        """Get value or raise the error."""
+        if self._error is not None:
+            raise self._error
+        return self._value  # type: ignore[return-value]
+
+    def unwrap_or(self, default: T) -> T:
+        """Get value or return default."""
+        if self._error is not None:
+            return default
+        return self._value  # type: ignore[return-value]
+
+# Usage preserves types
+def parse_config(path: str) -> Result[Config, ConfigError]:
+    try:
+        return Result(value=Config.from_file(path))
+    except ConfigError as e:
+        return Result(error=e)
+
+result = parse_config("config.yaml")
+if result.is_success:
+    config = result.unwrap()  # Type: Config
+```
+
+## Detailed worked examples and patterns
+
+Detailed sections (starting with `## Advanced Patterns`) live in `references/details.md`. Read that file when the navigation summary above is insufficient.
+
+## Best Practices Summary
+
+1. **Annotate all public APIs** - Functions, methods, class attributes
+2. **Use `T | None`** - Modern union syntax over `Optional[T]`
+3. **Run strict type checking** - `mypy --strict` in CI
+4. **Use generics** - Preserve type info in reusable code
+5. **Define protocols** - Structural typing for interfaces
+6. **Narrow types** - Use guards to help the type checker
+7. **Bound type vars** - Restrict generics to meaningful types
+8. **Create type aliases** - Meaningful names for complex types
+9. **Minimize `Any`** - Use specific types or generics. `Any` is acceptable for truly dynamic data or when interfacing with untyped third-party code
+10. **Document with types** - Types are enforceable documentation
diff --git a/skills/python-type-safety/references/details.md b/skills/python-type-safety/references/details.md
new file mode 100644
index 0000000..9bcaab6
--- /dev/null
+++ b/skills/python-type-safety/references/details.md
@@ -0,0 +1,237 @@
+# python-type-safety — detailed worked examples
+
+## Advanced Patterns
+
+### Pattern 5: Generic Repository
+
+Create type-safe data access patterns.
+
+```python
+from typing import TypeVar, Generic
+from abc import ABC, abstractmethod
+
+T = TypeVar("T")
+ID = TypeVar("ID")
+
+class Repository(ABC, Generic[T, ID]):
+    """Generic repository interface."""
+
+    @abstractmethod
+    async def get(self, id: ID) -> T | None:
+        """Get entity by ID."""
+        ...
+
+    @abstractmethod
+    async def save(self, entity: T) -> T:
+        """Save and return entity."""
+        ...
+
+    @abstractmethod
+    async def delete(self, id: ID) -> bool:
+        """Delete entity, return True if existed."""
+        ...
+
+class UserRepository(Repository[User, str]):
+    """Concrete repository for Users with string IDs."""
+
+    async def get(self, id: str) -> User | None:
+        row = await self._db.fetchrow(
+            "SELECT * FROM users WHERE id = $1", id
+        )
+        return User(**row) if row else None
+
+    async def save(self, entity: User) -> User:
+        ...
+
+    async def delete(self, id: str) -> bool:
+        ...
+```
+
+### Pattern 6: TypeVar with Bounds
+
+Restrict generic parameters to specific types.
+
+```python
+from typing import TypeVar
+from pydantic import BaseModel
+
+ModelT = TypeVar("ModelT", bound=BaseModel)
+
+def validate_and_create(model_cls: type[ModelT], data: dict) -> ModelT:
+    """Create a validated Pydantic model from dict."""
+    return model_cls.model_validate(data)
+
+# Works with any BaseModel subclass
+class User(BaseModel):
+    name: str
+    email: str
+
+user = validate_and_create(User, {"name": "Alice", "email": "a@b.com"})
+# user is typed as User
+
+# Type error: str is not a BaseModel subclass
+result = validate_and_create(str, {"name": "Alice"})  # Error!
+```
+
+### Pattern 7: Protocols for Structural Typing
+
+Define interfaces without requiring inheritance.
+
+```python
+from typing import Protocol, runtime_checkable
+
+@runtime_checkable
+class Serializable(Protocol):
+    """Any class that can be serialized to/from dict."""
+
+    def to_dict(self) -> dict:
+        ...
+
+    @classmethod
+    def from_dict(cls, data: dict) -> "Serializable":
+        ...
+
+# User satisfies Serializable without inheriting from it
+class User:
+    def __init__(self, id: str, name: str) -> None:
+        self.id = id
+        self.name = name
+
+    def to_dict(self) -> dict:
+        return {"id": self.id, "name": self.name}
+
+    @classmethod
+    def from_dict(cls, data: dict) -> "User":
+        return cls(id=data["id"], name=data["name"])
+
+def serialize(obj: Serializable) -> str:
+    """Works with any Serializable object."""
+    return json.dumps(obj.to_dict())
+
+# Works - User matches the protocol
+serialize(User("1", "Alice"))
+
+# Runtime checking with @runtime_checkable
+isinstance(User("1", "Alice"), Serializable)  # True
+```
+
+### Pattern 8: Common Protocol Patterns
+
+Define reusable structural interfaces.
+
+```python
+from typing import Protocol
+
+class Closeable(Protocol):
+    """Resource that can be closed."""
+    def close(self) -> None: ...
+
+class AsyncCloseable(Protocol):
+    """Async resource that can be closed."""
+    async def close(self) -> None: ...
+
+class Readable(Protocol):
+    """Object that can be read from."""
+    def read(self, n: int = -1) -> bytes: ...
+
+class HasId(Protocol):
+    """Object with an ID property."""
+    @property
+    def id(self) -> str: ...
+
+class Comparable(Protocol):
+    """Object that supports comparison."""
+    def __lt__(self, other: "Comparable") -> bool: ...
+    def __le__(self, other: "Comparable") -> bool: ...
+```
+
+### Pattern 9: Type Aliases
+
+Create meaningful type names.
+
+**Note:** The `type Alias = ...` statement syntax (PEP 695) was introduced in **Python 3.12**, not 3.10. For projects targeting earlier versions (including 3.10/3.11), use the `TypeAlias` annotation (PEP 613, available since Python 3.10).
+
+```python
+# Python 3.12+ type statement (PEP 695)
+type UserId = str
+type UserDict = dict[str, Any]
+
+# Python 3.12+ type statement with generics (PEP 695)
+type Handler[T] = Callable[[Request], T]
+type AsyncHandler[T] = Callable[[Request], Awaitable[T]]
+```
+
+```python
+# Python 3.10-3.11 style (needed for broader compatibility)
+from typing import TypeAlias
+from collections.abc import Callable, Awaitable
+
+UserId: TypeAlias = str
+Handler: TypeAlias = Callable[[Request], Response]
+```
+
+```python
+# Usage
+def register_handler(path: str, handler: Handler[Response]) -> None:
+    ...
+```
+
+### Pattern 10: Callable Types
+
+Type function parameters and callbacks.
+
+```python
+from collections.abc import Callable, Awaitable
+
+# Sync callback
+ProgressCallback = Callable[[int, int], None]  # (current, total)
+
+# Async callback
+AsyncHandler = Callable[[Request], Awaitable[Response]]
+
+# With named parameters (using Protocol)
+class OnProgress(Protocol):
+    def __call__(
+        self,
+        current: int,
+        total: int,
+        *,
+        message: str = "",
+    ) -> None: ...
+
+def process_items(
+    items: list[Item],
+    on_progress: ProgressCallback | None = None,
+) -> list[Result]:
+    for i, item in enumerate(items):
+        if on_progress:
+            on_progress(i, len(items))
+        ...
+```
+
+## Configuration
+
+### Strict Mode Checklist
+
+For `mypy --strict` compliance:
+
+```toml
+# pyproject.toml
+[tool.mypy]
+python_version = "3.12"
+strict = true
+warn_return_any = true
+warn_unused_ignores = true
+disallow_untyped_defs = true
+disallow_incomplete_defs = true
+no_implicit_optional = true
+```
+
+Incremental adoption goals:
+- All function parameters annotated
+- All return types annotated
+- Class attributes annotated
+- Minimize `Any` usage (acceptable for truly dynamic data)
+- Generic collections use type parameters (`list[str]` not `list`)
+
+For existing codebases, enable strict mode per-module using `# mypy: strict` or configure per-module overrides in `pyproject.toml`.
diff --git a/tests/inventory.test.mjs b/tests/inventory.test.mjs
index 38956b3..7377677 100644
--- a/tests/inventory.test.mjs
+++ b/tests/inventory.test.mjs
@@ -31,11 +31,12 @@ test('live skills are unique and include the three original packages plus BotKit
   assert.ok(names.includes('setup-bot'));
   assert.ok(names.includes('retro'));
   assert.ok(names.includes('simple-as-writing'));
+  assert.ok(names.includes('python-type-safety'));
   assert.ok(names.includes('tdd'));
   assert.ok(names.includes('matt-tdd'));
   assert.ok(names.includes('teach'));
   assert.ok(names.includes('matt-teach'));
-  assert.equal(names.length, 96);
+  assert.equal(names.length, 97);
 });
 
 test('pinned original sources remain present', async () => {