feat: enable mypy strict mode with comprehensive type improvements

Enable mypy strict mode and fix all type errors across the codebase:

Type System Enhancements:
- Enable strict mode in pyproject.toml
- Add schema parameter to client.get() and client.post() with overloads for type-safe returns
- Create type aliases in types_defs.py for YouTrack API responses
- Add return type annotations to all __init__ methods (-> None)
- Fix generic type parameters (FastMCP -> FastMCP[None])

Code Cleanup:
- Remove unreachable code from users.py and projects.py
- Simplify isinstance checks after type narrowing
- Remove unused close() methods from tool classes
- Remove backwards compatibility code for dict-based issue creation

API Resource Improvements:
- Use schema parameter in all client.get/post calls for proper typing
- Return typed responses (list[IssueDict], IssueCommentDict, etc.)
- Fix arg-type errors with explicit type annotations

Testing:
- Update test_add_comment to work with new schema parameter
- All 62 tests passing
- Mypy strict mode: 0 errors

Author: ivolnistov

pyproject.toml

@@ -152,17 +152,10 @@ line-ending = "auto"
 # MyPy configuration
 [tool.mypy]
 python_version = "3.12"
+strict = true
 show_column_numbers = true
 show_error_context = false
 follow_imports = "normal"
-ignore_missing_imports = true
-disallow_untyped_calls = false
-warn_return_any = false
-strict_optional = true
-warn_redundant_casts = true
-warn_unused_ignores = false
-disallow_untyped_defs = false  # Changed to false to allow gradual typing
-check_untyped_defs = false
 plugins = ["pydantic.mypy"]
 warn_unreachable = true
 mypy_path = ["src"]

src/youtrack_rocket_mcp/api/client.py

@@ -6,17 +6,19 @@
 import logging
 import random
 from types import TracebackType
-from typing import TYPE_CHECKING, Any
+from typing import TYPE_CHECKING, Any, TypeVar, cast, overload
+
+import httpx
+from pydantic import BaseModel, ConfigDict
 
 from youtrack_rocket_mcp.api.types import JSONDict, JSONValue, QueryParams
+from youtrack_rocket_mcp.config import config
+
+T = TypeVar('T')
 
 if TYPE_CHECKING:
     pass
 
-import httpx
-from pydantic import BaseModel, ConfigDict
-
-from youtrack_rocket_mcp.config import config
 
 logger = logging.getLogger(__name__)
 
@@ -204,33 +206,57 @@ async def _make_request(
         # Should never reach here
         raise YouTrackAPIError(f'Request failed after {self.max_retries} attempts')
 
-    async def get(self, endpoint: str, params: QueryParams | None = None, **kwargs: Any) -> JSONValue:
+    @overload
+    async def get(self, endpoint: str, params: QueryParams | None = None, *, schema: type[T], **kwargs: Any) -> T: ...
+
+    @overload
+    async def get(self, endpoint: str, params: QueryParams | None = None, **kwargs: Any) -> JSONValue: ...
+
+    async def get(
+        self, endpoint: str, params: QueryParams | None = None, schema: type[T] | None = None, **kwargs: Any
+    ) -> T | JSONValue:
         """
         Make a GET request.
 
         Args:
             endpoint: API endpoint
             params: Query parameters
+            schema: Optional type for return value (for type checking only)
             **kwargs: Additional request arguments
 
         Returns:
             Parsed JSON response
         """
-        return await self._make_request('GET', endpoint, params=params, **kwargs)
+        result = await self._make_request('GET', endpoint, params=params, **kwargs)
+        if schema is not None:
+            return cast(T, result)
+        return result
+
+    @overload
+    async def post(self, endpoint: str, data: JSONDict | None = None, *, schema: type[T], **kwargs: Any) -> T: ...
+
+    @overload
+    async def post(self, endpoint: str, data: JSONDict | None = None, **kwargs: Any) -> JSONValue: ...
 
-    async def post(self, endpoint: str, data: JSONDict | None = None, **kwargs: Any) -> JSONValue:
+    async def post(
+        self, endpoint: str, data: JSONDict | None = None, schema: type[T] | None = None, **kwargs: Any
+    ) -> T | JSONValue:
         """
         Make a POST request.
 
         Args:
             endpoint: API endpoint
             data: Request body data
+            schema: Optional type for return value (for type checking only)
             **kwargs: Additional request arguments
 
         Returns:
             Parsed JSON response
         """
-        return await self._make_request('POST', endpoint, data=data, **kwargs)
+        result = await self._make_request('POST', endpoint, data=data, **kwargs)
+        if schema is not None:
+            return cast(T, result)
+        return result
 
     async def put(self, endpoint: str, data: JSONDict | None = None, **kwargs: Any) -> JSONValue:
         """

src/youtrack_rocket_mcp/api/resources/issues.py

@@ -15,6 +15,7 @@
     get_field_types_from_project,
 )
 from youtrack_rocket_mcp.api.resources.projects import ProjectsClient
+from youtrack_rocket_mcp.api.schemas import IssueCommentDict
 from youtrack_rocket_mcp.api.types import CustomFieldData, FieldTypes, FieldValue, JSONDict
 from youtrack_rocket_mcp.utils.period_parser import parse_period_to_minutes
 
@@ -142,17 +143,17 @@ def _format_custom_field(field_key: str, field_value: FieldValue, field_type: st
             else:
                 field_entry['value'] = field_value
         elif field_type == 'SingleUserIssueCustomField':
-            field_entry['value'] = {'login': field_value} if isinstance(field_value, str) else field_value  # type: ignore[assignment]
+            field_entry['value'] = {'login': field_value} if isinstance(field_value, str) else field_value
         elif field_type in ['SingleEnumIssueCustomField', 'StateIssueCustomField']:
-            field_entry['value'] = {'name': field_value} if isinstance(field_value, str) else field_value  # type: ignore[assignment]
+            field_entry['value'] = {'name': field_value} if isinstance(field_value, str) else field_value
         elif field_type in [
             'DateIssueCustomField',
             'SimpleIssueCustomField',
             'TextIssueCustomField',
         ] or field_type.startswith('Multi'):
             field_entry['value'] = field_value
         else:
-            field_entry['value'] = {'name': field_value} if isinstance(field_value, str) else field_value  # type: ignore[assignment]
+            field_entry['value'] = {'name': field_value} if isinstance(field_value, str) else field_value
 
         return field_entry
 
@@ -274,12 +275,14 @@ async def create_issue(
                     issue_id = result['error_issue_id']
                     logger.info(f'Issue created (draft/incomplete): {issue_id}')
                     # Return an Issue object preserving input data
-                    return Issue(
-                        id=issue_id,
-                        summary=summary,
-                        description=description,
-                        project={'id': project_id},
-                        custom_fields=[],
+                    return Issue.model_validate(
+                        {
+                            'id': issue_id,
+                            'summary': summary,
+                            'description': description,
+                            'project': {'id': project_id},
+                            'custom_fields': [],
+                        },
                     )
 
                 # Normal successful response
@@ -290,17 +293,23 @@ async def create_issue(
                 try:
                     return Issue.model_validate(result)
                 except (ValueError, TypeError, KeyError):
-                    return Issue(
-                        id=issue_id,
-                        summary=summary or result.get('summary', ''),
-                        description=description or result.get('description'),
-                        project={'id': project_id},
+                    return Issue.model_validate(
+                        {
+                            'id': issue_id,
+                            'summary': summary or result.get('summary', ''),
+                            'description': description or result.get('description'),
+                            'project': {'id': project_id},
+                        }
                     )
             except (ValueError, TypeError, KeyError, AttributeError):
                 logger.exception('Error parsing response')
                 # Still return something if we have a response
-                return Issue(
-                    id=f'response-{response.status_code}', summary=summary or 'Created', project={'id': project_id}
+                return Issue.model_validate(
+                    {
+                        'id': f'response-{response.status_code}',
+                        'summary': summary or 'Created',
+                        'project': {'id': project_id},
+                    }
                 )
 
         except (httpx.HTTPError, ValueError) as e:
@@ -419,7 +428,7 @@ async def get_issue_comments(self, issue_id: str) -> list[JSONDict]:
                 return issue_response['comments']
             return []
 
-    async def add_comment(self, issue_id: str, text: str) -> JSONDict:
+    async def add_comment(self, issue_id: str, text: str) -> IssueCommentDict:
         """
         Add a comment to an issue.
 
@@ -431,4 +440,4 @@ async def add_comment(self, issue_id: str, text: str) -> JSONDict:
             The created comment data
         """
         data = {'text': text}
-        return await self.client.post(f'issues/{issue_id}/comments', data=data)
+        return await self.client.post(f'issues/{issue_id}/comments', data=data, schema=IssueCommentDict)

src/youtrack_rocket_mcp/api/resources/projects.py

@@ -8,6 +8,7 @@
 from pydantic import BaseModel, Field
 
 from youtrack_rocket_mcp.api.client import YouTrackClient
+from youtrack_rocket_mcp.api.schemas import IssueDict, ProjectCustomFieldDict
 from youtrack_rocket_mcp.api.types import JSONDict, JSONList
 
 logger = logging.getLogger(__name__)
@@ -111,7 +112,7 @@ async def get_project_by_name(self, project_name: str) -> Project | None:
 
         return None
 
-    async def get_project_issues(self, project_id: str, limit: int = 10) -> JSONList:
+    async def get_project_issues(self, project_id: str, limit: int = 10) -> list[IssueDict]:
         """
         Get issues for a specific project.
 
@@ -143,7 +144,7 @@ async def get_project_issues(self, project_id: str, limit: int = 10) -> JSONList
         params = {'$filter': f'project/id eq "{project_id}"', '$top': limit, 'fields': fields}
 
         try:
-            issues = await self.client.get('issues', params=params)
+            issues = await self.client.get('issues', params=params, schema=list[IssueDict])
             logger.info(f'Retrieved {len(issues) if isinstance(issues, list) else 0} issues')
         except (ValueError, KeyError, TypeError):
             logger.exception(f'Error getting issues for project {project_id}')
@@ -315,7 +316,7 @@ async def delete_project(self, project_id: str) -> None:
         """
         await self.client.delete(f'admin/projects/{project_id}')
 
-    async def get_custom_fields(self, project_id: str) -> JSONList:
+    async def get_custom_fields(self, project_id: str) -> list[ProjectCustomFieldDict]:
         """
         Get custom fields for a project with detailed information.
 
@@ -336,7 +337,9 @@ async def get_custom_fields(self, project_id: str) -> JSONList:
         params = {'fields': fields}
 
         try:
-            result = await self.client.get(f'admin/projects/{project_id}/customFields', params=params)
+            result = await self.client.get(
+                f'admin/projects/{project_id}/customFields', params=params, schema=list[ProjectCustomFieldDict]
+            )
             field_count = len(result) if isinstance(result, list) else 0
             logger.info(f'Successfully retrieved {field_count} custom fields for project {project_id}')
 
@@ -376,7 +379,9 @@ async def get_custom_fields(self, project_id: str) -> JSONList:
             logger.exception(f'Error getting detailed custom fields for project {project_id}')
             # Fallback to basic request without fields parameter
             try:
-                basic_result = await self.client.get(f'admin/projects/{project_id}/customFields')
+                basic_result = await self.client.get(
+                    f'admin/projects/{project_id}/customFields', schema=list[ProjectCustomFieldDict]
+                )
                 logger.warning(f'Falling back to basic custom fields request for project {project_id}')
             except (ValueError, KeyError, TypeError):
                 logger.exception('Fallback request also failed')
@@ -386,7 +391,9 @@ async def get_custom_fields(self, project_id: str) -> JSONList:
         else:
             return enhanced_fields
 
-    async def add_custom_field(self, project_id: str, field_id: str, empty_field_text: str | None = None) -> JSONDict:
+    async def add_custom_field(
+        self, project_id: str, field_id: str, empty_field_text: str | None = None
+    ) -> ProjectCustomFieldDict:
         """
         Add a custom field to a project.
 
@@ -403,7 +410,9 @@ async def add_custom_field(self, project_id: str, field_id: str, empty_field_tex
         if empty_field_text:
             data['emptyFieldText'] = empty_field_text  # type: ignore[assignment]
 
-        return await self.client.post(f'admin/projects/{project_id}/customFields', data=data)
+        return await self.client.post(
+            f'admin/projects/{project_id}/customFields', data=data, schema=ProjectCustomFieldDict
+        )
 
     async def get_project_fields_from_issues(self, project_id: str) -> JSONDict:
         """

src/youtrack_rocket_mcp/api/resources/search.py

@@ -2,15 +2,18 @@
 YouTrack Search API client with advanced search capabilities.
 """
 
+from typing import Any
+
 from youtrack_rocket_mcp.api.client import YouTrackClient
-from youtrack_rocket_mcp.api.types import CustomFieldData, JSONList
+from youtrack_rocket_mcp.api.schemas import CustomFieldSettingDict, IssueDict
+from youtrack_rocket_mcp.api.types import CustomFieldData
 
 
 class SearchClient:
     """Client for advanced search operations in YouTrack."""
 
     @staticmethod
-    def format_custom_fields(custom_fields: list) -> dict[str, str | None]:
+    def format_custom_fields(custom_fields: list[Any]) -> dict[str, str | None]:
         """
         Format custom fields from array to dictionary {name: value}.
 
@@ -74,7 +77,7 @@ async def search_issues(
         sort_by: str | None = None,
         sort_order: str | None = None,
         custom_fields: list[str] | None = None,
-    ) -> JSONList:
+    ) -> list[IssueDict]:
         """
         Search for issues with advanced query capabilities.
 
@@ -130,7 +133,7 @@ async def search_issues(
                 params['$sortOrder'] = sort_order.lower()
 
         # Make the API request
-        issues = await self.client.get('issues', params=params)
+        issues = await self.client.get('issues', params=params, schema=list[IssueDict])
 
         # Format custom fields for each issue
         for issue in issues:
@@ -143,7 +146,7 @@ async def search_issues(
 
     async def search_with_custom_field_values(
         self, query: str, custom_field_values: CustomFieldData, limit: int = 10
-    ) -> JSONList:
+    ) -> list[IssueDict]:
         """
         Search for issues with specific custom field values.
 
@@ -194,7 +197,7 @@ async def search_with_filter(
         updated_before: str | None = None,
         custom_fields: CustomFieldData | None = None,
         limit: int = 10,
-    ) -> JSONList:
+    ) -> list[IssueDict]:
         """
         Search for issues using a structured filter approach.
 
@@ -260,7 +263,7 @@ async def search_with_filter(
             return await self.search_with_custom_field_values(base_query, custom_fields, limit)
         return await self.search_issues(base_query, limit=limit)
 
-    async def get_available_custom_fields(self, project_id: str | None = None) -> JSONList:
+    async def get_available_custom_fields(self, project_id: str | None = None) -> list[CustomFieldSettingDict]:
         """
         Get all available custom fields, optionally for a specific project.
 
@@ -280,4 +283,4 @@ async def get_available_custom_fields(self, project_id: str | None = None) -> JS
         fields = 'id,name,localizedName,fieldType(id,name),isPrivate,isPublic,aliases'
         params = {'fields': fields}
 
-        return await self.client.get(endpoint, params=params)
+        return await self.client.get(endpoint, params=params, schema=list[CustomFieldSettingDict])

src/youtrack_rocket_mcp/api/resources/users.py

@@ -7,7 +7,7 @@
 from pydantic import BaseModel
 
 from youtrack_rocket_mcp.api.client import YouTrackClient
-from youtrack_rocket_mcp.api.types import JSONList
+from youtrack_rocket_mcp.api.schemas import UserGroupDict
 
 logger = logging.getLogger(__name__)
 
@@ -114,7 +114,7 @@ async def get_user_by_login(self, login: str) -> User | None:
 
         return None
 
-    async def get_user_groups(self, user_id: str) -> JSONList:
+    async def get_user_groups(self, user_id: str) -> list[UserGroupDict]:
         """
         Get groups for a user.
 
@@ -124,7 +124,7 @@ async def get_user_groups(self, user_id: str) -> JSONList:
         Returns:
             List of group data
         """
-        return await self.client.get(f'users/{user_id}/groups')
+        return await self.client.get(f'users/{user_id}/groups', schema=list[UserGroupDict])
 
     async def check_user_permissions(self, user_id: str, permission: str) -> bool:
         """