diff --git a/ci/bump_version.py b/ci/bump_version.py
index e18dd7a8..977b554b 100644
--- a/ci/bump_version.py
+++ b/ci/bump_version.py
@@ -12,7 +12,7 @@
 
 def run_command(
     cmd: list[str], capture_output: bool = True
-) -> subprocess.CompletedProcess:
+) -> subprocess.CompletedProcess[str]:
     """Run a command and return the result."""
     print(f"Running: {' '.join(cmd)}")
     result = subprocess.run(cmd, capture_output=capture_output, text=True)
@@ -37,7 +37,7 @@ def get_current_version() -> str:
     raise ValueError("Could not find current_version in .bumpversion.toml")
 
 
-def main():
+def main() -> None:
     parser = argparse.ArgumentParser(
         description="Bump version in Python project using bump-my-version"
     )
diff --git a/ci/calculate_version.py b/ci/calculate_version.py
index 07130ce4..710efe7c 100644
--- a/ci/calculate_version.py
+++ b/ci/calculate_version.py
@@ -10,7 +10,9 @@
 from packaging import version
 
 
-def calculate_next_version(current_version, release_type, channel):
+def calculate_next_version(
+    current_version: str, release_type: str, channel: str
+) -> str:
     """Calculate the next version based on release type and channel"""
 
     # Parse current version
@@ -49,7 +51,7 @@ def calculate_next_version(current_version, release_type, channel):
     return new_version
 
 
-def main():
+def main() -> None:
     parser = argparse.ArgumentParser(description="Calculate next version")
     parser.add_argument("--current", required=True, help="Current version")
     parser.add_argument(
diff --git a/ci/check_pylance_release.py b/ci/check_pylance_release.py
index 5cf9887c..cc3b3eac 100644
--- a/ci/check_pylance_release.py
+++ b/ci/check_pylance_release.py
@@ -12,11 +12,12 @@
 from collections.abc import Iterable, Sequence
 from dataclasses import dataclass
 from pathlib import Path
+from typing import Any
 
-try:
+if sys.version_info >= (3, 11):
     import tomllib
-except ModuleNotFoundError:
-    import tomli as tomllib  # type: ignore
+else:  # pragma: no cover - Python 3.10 fallback
+    import tomli as tomllib
 
 LANCE_REPO = "lance-format/lance"
 
@@ -223,7 +224,7 @@ def determine_latest_tag(tags: Iterable[TagInfo]) -> TagInfo:
     return max(tags, key=lambda tag: tag.semver)
 
 
-def write_outputs(args: argparse.Namespace, payload: dict) -> None:
+def write_outputs(args: argparse.Namespace, payload: dict[str, Any]) -> None:
     target = getattr(args, "github_output", None)
     if not target:
         return
diff --git a/ci/generate_release_notes.py b/ci/generate_release_notes.py
index abb7cc5c..f5412148 100644
--- a/ci/generate_release_notes.py
+++ b/ci/generate_release_notes.py
@@ -12,9 +12,13 @@
 import urllib.error
 import urllib.request
 from datetime import datetime
+from typing import Any, Optional
 
+#: A parsed ``git log`` entry: sha / message / author / email.
+Commit = dict[str, str]
 
-def get_github_api_data(url, token):
+
+def get_github_api_data(url: str, token: str) -> Optional[Any]:
     """Fetch data from GitHub API"""
     headers = {
         "Authorization": f"token {token}",
@@ -30,7 +34,7 @@ def get_github_api_data(url, token):
         return None
 
 
-def get_commits_since_last_tag(tag):
+def get_commits_since_last_tag(tag: str) -> tuple[list[Commit], Optional[str]]:
     """Get all commits since the last tag"""
     try:
         # Get the previous tag
@@ -67,7 +71,7 @@ def get_commits_since_last_tag(tag):
         if not commits:
             return [], previous_tag
 
-        commit_list = []
+        commit_list: list[Commit] = []
         for line in commits.split("\n"):
             if line:
                 parts = line.split("|")
@@ -88,9 +92,9 @@ def get_commits_since_last_tag(tag):
         return [], None
 
 
-def categorize_commits(commits):
+def categorize_commits(commits: list[Commit]) -> dict[str, list[Commit]]:
     """Categorize commits based on conventional commit format"""
-    categories = {
+    categories: dict[str, list[Commit]] = {
         "Features": [],
         "Bug Fixes": [],
         "Performance": [],
@@ -129,7 +133,7 @@ def categorize_commits(commits):
     return categories
 
 
-def extract_pr_number(message):
+def extract_pr_number(message: str) -> Optional[str]:
     """Extract PR number from commit message"""
     # Look for patterns like (#123) or #123
     match = re.search(r"#(\d+)", message)
@@ -138,7 +142,13 @@ def extract_pr_number(message):
     return None
 
 
-def generate_release_notes(tag, repo, token, commits, previous_tag):
+def generate_release_notes(
+    tag: str,
+    repo: str,
+    token: Optional[str],
+    commits: list[Commit],
+    previous_tag: Optional[str],
+) -> str:
     """Generate release notes in Markdown format"""
 
     notes = []
@@ -223,7 +233,7 @@ def generate_release_notes(tag, repo, token, commits, previous_tag):
     return "\n".join(notes)
 
 
-def main():
+def main() -> None:
     parser = argparse.ArgumentParser(description="Generate release notes")
     parser.add_argument("--tag", required=True, help="Release tag")
     parser.add_argument("--repo", required=True, help="GitHub repository (owner/repo)")