diff --git a/src/databricks/labs/ucx/account/aggregate.py b/src/databricks/labs/ucx/account/aggregate.py
index 237ebfebf1..be52d60067 100644
--- a/src/databricks/labs/ucx/account/aggregate.py
+++ b/src/databricks/labs/ucx/account/aggregate.py
@@ -49,7 +49,7 @@ def __init__(
         self._workspace_context_factory = workspace_context_factory
 
     @cached_property
-    def _workspace_contexts(self):
+    def _workspace_contexts(self) -> list[WorkspaceContext]:
         contexts = []
         for workspace_client in self._account_workspaces.workspace_clients():
             ctx = self._workspace_context_factory(workspace_client)
diff --git a/src/databricks/labs/ucx/cli.py b/src/databricks/labs/ucx/cli.py
index b9b75b1640..a6e1bb57bd 100644
--- a/src/databricks/labs/ucx/cli.py
+++ b/src/databricks/labs/ucx/cli.py
@@ -593,11 +593,19 @@ def assign_metastore(
     ctx: AccountContext | None = None,
 ):
     """Assign metastore to a workspace"""
+    if workspace_id is None:
+        logger.error("--workspace-id is a required parameter.")
+        return
+    try:
+        workspace_id_casted = int(workspace_id)
+    except ValueError:
+        logger.error("--workspace-id should be an integer.")
+        return
     logger.info(f"Account ID: {a.config.account_id}")
     ctx = ctx or AccountContext(a)
     ctx.account_metastores.assign_metastore(
         ctx.prompts,
-        workspace_id,
+        workspace_id_casted,
         metastore_id=metastore_id,
         default_catalog=default_catalog,
     )
@@ -635,7 +643,7 @@ def migrate_tables(
         deployed_workflows = workspace_context.deployed_workflows
         deployed_workflows.run_workflow("migrate-tables")
 
-        tables = workspace_context.tables_crawler.snapshot()
+        tables = list(workspace_context.tables_crawler.snapshot())
         hiveserde_tables = [table for table in tables if table.what == What.EXTERNAL_HIVESERDE]
         if len(hiveserde_tables) > 0:
             percentage_hiveserde_tables = len(hiveserde_tables) / len(tables) * 100
diff --git a/src/databricks/labs/ucx/contexts/account_cli.py b/src/databricks/labs/ucx/contexts/account_cli.py
index 9f88049f65..ef4b1282af 100644
--- a/src/databricks/labs/ucx/contexts/account_cli.py
+++ b/src/databricks/labs/ucx/contexts/account_cli.py
@@ -19,21 +19,21 @@ def account_client(self) -> AccountClient:
         return self._ac
 
     @cached_property
-    def workspace_ids(self):
+    def workspace_ids(self) -> list[int]:
         return [int(_.strip()) for _ in self.named_parameters.get("workspace_ids", "").split(",") if _]
 
     @cached_property
-    def account_workspaces(self):
+    def account_workspaces(self) -> AccountWorkspaces:
         return AccountWorkspaces(self.account_client, self.workspace_ids)
 
     @cached_property
-    def account_aggregate(self):
+    def account_aggregate(self) -> AccountAggregate:
         return AccountAggregate(self.account_workspaces)
 
     @cached_property
-    def is_account_install(self):
+    def is_account_install(self) -> bool:
         return environ.get("UCX_FORCE_INSTALL") == "account"
 
     @cached_property
-    def account_metastores(self):
+    def account_metastores(self) -> AccountMetastores:
         return AccountMetastores(self.account_client)
diff --git a/src/databricks/labs/ucx/contexts/application.py b/src/databricks/labs/ucx/contexts/application.py
index 6e2e66c5c1..a1ff1d63ef 100644
--- a/src/databricks/labs/ucx/contexts/application.py
+++ b/src/databricks/labs/ucx/contexts/application.py
@@ -1,5 +1,7 @@
 import abc
 import logging
+import sys
+from collections.abc import Callable, Iterable
 from datetime import timedelta
 from functools import cached_property
 from pathlib import Path
@@ -28,12 +30,14 @@
 from databricks.labs.ucx.hive_metastore import ExternalLocations, Mounts, TablesCrawler
 from databricks.labs.ucx.hive_metastore.catalog_schema import CatalogSchema
 from databricks.labs.ucx.hive_metastore.grants import (
+    ACLMigrator,
+    AwsACL,
     AzureACL,
+    ComputeLocations,
+    Grant,
     GrantsCrawler,
-    PrincipalACL,
-    AwsACL,
     MigrateGrants,
-    ACLMigrator,
+    PrincipalACL,
 )
 from databricks.labs.ucx.hive_metastore.mapping import TableMapping
 from databricks.labs.ucx.hive_metastore.table_migration_status import TableMigrationIndex
@@ -45,15 +49,15 @@
 from databricks.labs.ucx.hive_metastore.udfs import UdfsCrawler
 from databricks.labs.ucx.hive_metastore.verification import VerifyHasMetastore
 from databricks.labs.ucx.installer.workflows import DeployedWorkflows
+from databricks.labs.ucx.source_code.graph import DependencyResolver
 from databricks.labs.ucx.source_code.jobs import WorkflowLinter
+from databricks.labs.ucx.source_code.known import KnownList
+from databricks.labs.ucx.source_code.linters.files import FileLoader, FolderLoader, ImportFileResolver
 from databricks.labs.ucx.source_code.notebooks.loaders import (
     NotebookResolver,
     NotebookLoader,
 )
-from databricks.labs.ucx.source_code.linters.files import FileLoader, FolderLoader, ImportFileResolver
 from databricks.labs.ucx.source_code.path_lookup import PathLookup
-from databricks.labs.ucx.source_code.graph import DependencyResolver
-from databricks.labs.ucx.source_code.known import KnownList
 from databricks.labs.ucx.source_code.queries import QueryLinter
 from databricks.labs.ucx.source_code.redash import Redash
 from databricks.labs.ucx.workspace_access import generic, redash
@@ -63,6 +67,11 @@
 from databricks.labs.ucx.workspace_access.secrets import SecretScopesSupport
 from databricks.labs.ucx.workspace_access.tacl import TableAclSupport
 
+if sys.version_info >= (3, 11):
+    from typing import Self
+else:
+    from typing_extensions import Self
+
 # "Service Factories" would always have a lot of public methods.
 # This is because they are responsible for creating objects that are
 # used throughout the application. That being said, we'll do best
@@ -79,7 +88,7 @@ def __init__(self, named_parameters: dict[str, str] | None = None):
             named_parameters = {}
         self._named_parameters = named_parameters
 
-    def replace(self, **kwargs):
+    def replace(self, **kwargs) -> Self:
         """Replace cached properties for unit testing purposes."""
         for key, value in kwargs.items():
             self.__dict__[key] = value
@@ -102,11 +111,11 @@ def named_parameters(self) -> dict[str, str]:
         return self._named_parameters
 
     @cached_property
-    def product_info(self):
+    def product_info(self) -> ProductInfo:
         return ProductInfo.from_class(WorkspaceConfig)
 
     @cached_property
-    def installation(self):
+    def installation(self) -> Installation:
         return Installation.current(self.workspace_client, self.product_info.product_name())
 
     @cached_property
@@ -134,7 +143,7 @@ def inventory_database(self) -> str:
         return self.config.inventory_database
 
     @cached_property
-    def workspace_listing(self):
+    def workspace_listing(self) -> generic.WorkspaceListing:
         return generic.WorkspaceListing(
             self.workspace_client,
             self.sql_backend,
@@ -144,7 +153,7 @@ def workspace_listing(self):
         )
 
     @cached_property
-    def generic_permissions_support(self):
+    def generic_permissions_support(self) -> generic.GenericPermissionsSupport:
         models_listing = generic.models_listing(self.workspace_client, self.config.num_threads)
         acl_listing = [
             generic.Listing(self.workspace_client.clusters.list, "cluster_id", "clusters"),
@@ -169,7 +178,7 @@ def generic_permissions_support(self):
         )
 
     @cached_property
-    def redash_permissions_support(self):
+    def redash_permissions_support(self) -> redash.RedashPermissionsSupport:
         acl_listing = [
             redash.Listing(self.workspace_client.alerts.list, sql.ObjectTypePlural.ALERTS),
             redash.Listing(self.workspace_client.dashboards.list, sql.ObjectTypePlural.DASHBOARDS),
@@ -182,17 +191,17 @@ def redash_permissions_support(self):
         )
 
     @cached_property
-    def scim_entitlements_support(self):
+    def scim_entitlements_support(self) -> ScimSupport:
         return ScimSupport(self.workspace_client, include_object_permissions=self.config.include_object_permissions)
 
     @cached_property
-    def secret_scope_acl_support(self):
+    def secret_scope_acl_support(self) -> SecretScopesSupport:
         return SecretScopesSupport(
             self.workspace_client, include_object_permissions=self.config.include_object_permissions
         )
 
     @cached_property
-    def legacy_table_acl_support(self):
+    def legacy_table_acl_support(self) -> TableAclSupport:
         return TableAclSupport(
             self.grants_crawler,
             self.sql_backend,
@@ -200,7 +209,7 @@ def legacy_table_acl_support(self):
         )
 
     @cached_property
-    def permission_manager(self):
+    def permission_manager(self) -> PermissionManager:
         return PermissionManager(
             self.sql_backend,
             self.inventory_database,
@@ -214,7 +223,7 @@ def permission_manager(self):
         )
 
     @cached_property
-    def group_manager(self):
+    def group_manager(self) -> GroupManager:
         return GroupManager(
             self.sql_backend,
             self.workspace_client,
@@ -228,19 +237,19 @@ def group_manager(self):
         )
 
     @cached_property
-    def grants_crawler(self):
+    def grants_crawler(self) -> GrantsCrawler:
         return GrantsCrawler(self.tables_crawler, self.udfs_crawler, self.config.include_databases)
 
     @cached_property
-    def udfs_crawler(self):
+    def udfs_crawler(self) -> UdfsCrawler:
         return UdfsCrawler(self.sql_backend, self.inventory_database, self.config.include_databases)
 
     @cached_property
-    def tables_crawler(self):
+    def tables_crawler(self) -> TablesCrawler:
         return TablesCrawler(self.sql_backend, self.inventory_database, self.config.include_databases)
 
     @cached_property
-    def tables_migrator(self):
+    def tables_migrator(self) -> TablesMigrator:
         return TablesMigrator(
             self.tables_crawler,
             self.workspace_client,
@@ -251,7 +260,7 @@ def tables_migrator(self):
         )
 
     @cached_property
-    def acl_migrator(self):
+    def acl_migrator(self) -> ACLMigrator:
         return ACLMigrator(
             self.tables_crawler,
             self.workspace_info,
@@ -260,8 +269,8 @@ def acl_migrator(self):
         )
 
     @cached_property
-    def migrate_grants(self):
-        grant_loaders = [
+    def migrate_grants(self) -> MigrateGrants:
+        grant_loaders: list[Callable[[], Iterable[Grant]]] = [
             self.grants_crawler.snapshot,
             self.principal_acl.get_interactive_cluster_grants,
         ]
@@ -272,23 +281,23 @@ def migrate_grants(self):
         )
 
     @cached_property
-    def table_move(self):
+    def table_move(self) -> TableMove:
         return TableMove(self.workspace_client, self.sql_backend)
 
     @cached_property
-    def mounts_crawler(self):
+    def mounts_crawler(self) -> Mounts:
         return Mounts(self.sql_backend, self.workspace_client, self.inventory_database)
 
     @cached_property
-    def azure_service_principal_crawler(self):
+    def azure_service_principal_crawler(self) -> AzureServicePrincipalCrawler:
         return AzureServicePrincipalCrawler(self.workspace_client, self.sql_backend, self.inventory_database)
 
     @cached_property
-    def external_locations(self):
+    def external_locations(self) -> ExternalLocations:
         return ExternalLocations(self.workspace_client, self.sql_backend, self.inventory_database)
 
     @cached_property
-    def azure_acl(self):
+    def azure_acl(self) -> AzureACL:
         return AzureACL(
             self.workspace_client,
             self.sql_backend,
@@ -297,7 +306,7 @@ def azure_acl(self):
         )
 
     @cached_property
-    def aws_acl(self):
+    def aws_acl(self) -> AwsACL:
         return AwsACL(
             self.workspace_client,
             self.sql_backend,
@@ -305,7 +314,7 @@ def aws_acl(self):
         )
 
     @cached_property
-    def principal_locations_retriever(self):
+    def principal_locations_retriever(self) -> Callable[[], list[ComputeLocations]]:
         def inner():
             if self.is_azure:
                 return self.azure_acl.get_eligible_locations_principals()
@@ -316,7 +325,7 @@ def inner():
         return inner
 
     @cached_property
-    def principal_acl(self):
+    def principal_acl(self) -> PrincipalACL:
         return PrincipalACL(
             self.workspace_client,
             self.sql_backend,
@@ -327,7 +336,7 @@ def principal_acl(self):
         )
 
     @cached_property
-    def migration_status_refresher(self):
+    def migration_status_refresher(self) -> TableMigrationStatusRefresher:
         return TableMigrationStatusRefresher(
             self.workspace_client,
             self.sql_backend,
@@ -336,15 +345,15 @@ def migration_status_refresher(self):
         )
 
     @cached_property
-    def iam_credential_manager(self):
+    def iam_credential_manager(self) -> CredentialManager:
         return CredentialManager(self.workspace_client)
 
     @cached_property
-    def table_mapping(self):
+    def table_mapping(self) -> TableMapping:
         return TableMapping(self.installation, self.workspace_client, self.sql_backend)
 
     @cached_property
-    def catalog_schema(self):
+    def catalog_schema(self) -> CatalogSchema:
         return CatalogSchema(
             self.workspace_client,
             self.table_mapping,
@@ -355,31 +364,31 @@ def catalog_schema(self):
         )
 
     @cached_property
-    def verify_timeout(self):
+    def verify_timeout(self) -> timedelta:
         return timedelta(minutes=2)
 
     @cached_property
-    def wheels(self):
+    def wheels(self) -> WheelsV2:
         return WheelsV2(self.installation, self.product_info)
 
     @cached_property
-    def install_state(self):
+    def install_state(self) -> InstallState:
         return InstallState.from_installation(self.installation)
 
     @cached_property
-    def deployed_workflows(self):
+    def deployed_workflows(self) -> DeployedWorkflows:
         return DeployedWorkflows(self.workspace_client, self.install_state)
 
     @cached_property
-    def workspace_info(self):
+    def workspace_info(self) -> WorkspaceInfo:
         return WorkspaceInfo(self.installation, self.workspace_client)
 
     @cached_property
-    def verify_has_metastore(self):
+    def verify_has_metastore(self) -> VerifyHasMetastore:
         return VerifyHasMetastore(self.workspace_client)
 
     @cached_property
-    def pip_resolver(self):
+    def pip_resolver(self) -> PythonLibraryResolver:
         return PythonLibraryResolver(self.allow_list)
 
     @cached_property
@@ -387,37 +396,37 @@ def notebook_loader(self) -> NotebookLoader:
         return NotebookLoader()
 
     @cached_property
-    def notebook_resolver(self):
+    def notebook_resolver(self) -> NotebookResolver:
         return NotebookResolver(self.notebook_loader)
 
     @cached_property
-    def site_packages_path(self):
+    def site_packages_path(self) -> Path:
         lookup = self.path_lookup
         return next(path for path in lookup.library_roots if "site-packages" in path.as_posix())
 
     @cached_property
-    def path_lookup(self):
+    def path_lookup(self) -> PathLookup:
         # TODO find a solution to enable a different cwd per job/task (maybe it's not necessary or possible?)
         return PathLookup.from_sys_path(Path.cwd())
 
     @cached_property
-    def file_loader(self):
+    def file_loader(self) -> FileLoader:
         return FileLoader()
 
     @cached_property
-    def folder_loader(self):
+    def folder_loader(self) -> FolderLoader:
         return FolderLoader(self.notebook_loader, self.file_loader)
 
     @cached_property
-    def allow_list(self):
+    def allow_list(self) -> KnownList:
         return KnownList()
 
     @cached_property
-    def file_resolver(self):
+    def file_resolver(self) -> ImportFileResolver:
         return ImportFileResolver(self.file_loader, self.allow_list)
 
     @cached_property
-    def dependency_resolver(self):
+    def dependency_resolver(self) -> DependencyResolver:
         return DependencyResolver(
             self.pip_resolver, self.notebook_resolver, self.file_resolver, self.file_resolver, self.path_lookup
         )
@@ -435,7 +444,7 @@ def workflow_linter(self) -> WorkflowLinter:
         )
 
     @cached_property
-    def query_linter(self):
+    def query_linter(self) -> QueryLinter:
         return QueryLinter(
             self.workspace_client,
             TableMigrationIndex([]),  # TODO: bring back self.tables_migrator.index()
@@ -444,11 +453,11 @@ def query_linter(self):
         )
 
     @cached_property
-    def directfs_access_crawler_for_paths(self):
+    def directfs_access_crawler_for_paths(self) -> DirectFsAccessCrawler:
         return DirectFsAccessCrawler.for_paths(self.sql_backend, self.inventory_database)
 
     @cached_property
-    def directfs_access_crawler_for_queries(self):
+    def directfs_access_crawler_for_queries(self) -> DirectFsAccessCrawler:
         return DirectFsAccessCrawler.for_queries(self.sql_backend, self.inventory_database)
 
     @cached_property
@@ -460,7 +469,7 @@ def used_tables_crawler_for_queries(self):
         return UsedTablesCrawler.for_queries(self.sql_backend, self.inventory_database)
 
     @cached_property
-    def redash(self):
+    def redash(self) -> Redash:
         return Redash(
             self.migration_status_refresher.index(),
             self.workspace_client,
@@ -468,23 +477,23 @@ def redash(self):
         )
 
     @cached_property
-    def metadata_retriever(self):
+    def metadata_retriever(self) -> DatabricksTableMetadataRetriever:
         return DatabricksTableMetadataRetriever(self.sql_backend)
 
     @cached_property
-    def schema_comparator(self):
+    def schema_comparator(self) -> StandardSchemaComparator:
         return StandardSchemaComparator(self.metadata_retriever)
 
     @cached_property
-    def data_profiler(self):
+    def data_profiler(self) -> StandardDataProfiler:
         return StandardDataProfiler(self.sql_backend, self.metadata_retriever)
 
     @cached_property
-    def data_comparator(self):
+    def data_comparator(self) -> StandardDataComparator:
         return StandardDataComparator(self.sql_backend, self.data_profiler)
 
     @cached_property
-    def migration_recon(self):
+    def migration_recon(self) -> MigrationRecon:
         return MigrationRecon(
             self.sql_backend,
             self.inventory_database,
diff --git a/src/databricks/labs/ucx/contexts/workflow_task.py b/src/databricks/labs/ucx/contexts/workflow_task.py
index 715fb5c67d..14a6130fca 100644
--- a/src/databricks/labs/ucx/contexts/workflow_task.py
+++ b/src/databricks/labs/ucx/contexts/workflow_task.py
@@ -46,16 +46,16 @@ def sql_backend(self) -> SqlBackend:
         return RuntimeBackend(debug_truncate_bytes=self.connect_config.debug_truncate_bytes)
 
     @cached_property
-    def installation(self):
+    def installation(self) -> Installation:
         install_folder = self._config_path.parent.as_posix().removeprefix("/Workspace")
         return Installation(self.workspace_client, "ucx", install_folder=install_folder)
 
     @cached_property
-    def jobs_crawler(self):
+    def jobs_crawler(self) -> JobsCrawler:
         return JobsCrawler(self.workspace_client, self.sql_backend, self.inventory_database)
 
     @cached_property
-    def submit_runs_crawler(self):
+    def submit_runs_crawler(self) -> SubmitRunsCrawler:
         return SubmitRunsCrawler(
             self.workspace_client,
             self.sql_backend,
@@ -64,31 +64,32 @@ def submit_runs_crawler(self):
         )
 
     @cached_property
-    def clusters_crawler(self):
+    def clusters_crawler(self) -> ClustersCrawler:
         return ClustersCrawler(self.workspace_client, self.sql_backend, self.inventory_database)
 
     @cached_property
-    def pipelines_crawler(self):
+    def pipelines_crawler(self) -> PipelinesCrawler:
         return PipelinesCrawler(self.workspace_client, self.sql_backend, self.inventory_database)
 
     @cached_property
-    def table_size_crawler(self):
+    def table_size_crawler(self) -> TableSizeCrawler:
         return TableSizeCrawler(self.sql_backend, self.inventory_database, self.config.include_databases)
 
     @cached_property
-    def policies_crawler(self):
+    def policies_crawler(self) -> PoliciesCrawler:
         return PoliciesCrawler(self.workspace_client, self.sql_backend, self.inventory_database)
 
     @cached_property
-    def global_init_scripts_crawler(self):
+    def global_init_scripts_crawler(self) -> GlobalInitScriptCrawler:
         return GlobalInitScriptCrawler(self.workspace_client, self.sql_backend, self.inventory_database)
 
     @cached_property
     def tables_crawler(self):
+        # TODO: Update tables crawler inheritance to specify return type hint
         return FasterTableScanCrawler(self.sql_backend, self.inventory_database)
 
     @cached_property
-    def tables_in_mounts(self):
+    def tables_in_mounts(self) -> TablesInMounts:
         return TablesInMounts(
             self.sql_backend,
             self.workspace_client,
@@ -100,7 +101,7 @@ def tables_in_mounts(self):
         )
 
     @cached_property
-    def task_run_warning_recorder(self):
+    def task_run_warning_recorder(self) -> TaskRunWarningRecorder:
         return TaskRunWarningRecorder(
             self._config_path.parent,
             self.named_parameters["workflow"],
diff --git a/src/databricks/labs/ucx/contexts/workspace_cli.py b/src/databricks/labs/ucx/contexts/workspace_cli.py
index 2c4830a863..5191c1792e 100644
--- a/src/databricks/labs/ucx/contexts/workspace_cli.py
+++ b/src/databricks/labs/ucx/contexts/workspace_cli.py
@@ -1,6 +1,7 @@
 import logging
 import os
 import shutil
+from collections.abc import Callable
 from functools import cached_property
 
 from databricks.labs.lsql.backends import SqlBackend, StatementExecutionBackend
@@ -42,11 +43,11 @@ def sql_backend(self) -> SqlBackend:
         return StatementExecutionBackend(self.workspace_client, self.config.warehouse_id)
 
     @cached_property
-    def cluster_access(self):
+    def cluster_access(self) -> ClusterAccess:
         return ClusterAccess(self.installation, self.workspace_client, self.prompts)
 
     @cached_property
-    def azure_cli_authenticated(self):
+    def azure_cli_authenticated(self) -> bool:
         if not self.is_azure:
             raise NotImplementedError("Azure only")
         if self.connect_config.auth_type != "azure-cli":
@@ -54,7 +55,7 @@ def azure_cli_authenticated(self):
         return True
 
     @cached_property
-    def azure_management_client(self):
+    def azure_management_client(self) -> AzureAPIClient:
         if not self.azure_cli_authenticated:
             raise NotImplementedError
         return AzureAPIClient(
@@ -63,7 +64,7 @@ def azure_management_client(self):
         )
 
     @cached_property
-    def microsoft_graph_client(self):
+    def microsoft_graph_client(self) -> AzureAPIClient:
         if not self.azure_cli_authenticated:
             raise NotImplementedError
         return AzureAPIClient("https://graph.microsoft.com", "https://graph.microsoft.com")
@@ -76,7 +77,7 @@ def azure_subscription_ids(self) -> list[str]:
         return subscription_ids.split(",")
 
     @cached_property
-    def azure_resources(self):
+    def azure_resources(self) -> AzureResources:
         return AzureResources(
             self.azure_management_client,
             self.microsoft_graph_client,
@@ -84,7 +85,7 @@ def azure_resources(self):
         )
 
     @cached_property
-    def azure_resource_permissions(self):
+    def azure_resource_permissions(self) -> AzureResourcePermissions:
         return AzureResourcePermissions(
             self.installation,
             self.workspace_client,
@@ -93,11 +94,11 @@ def azure_resource_permissions(self):
         )
 
     @cached_property
-    def azure_credential_manager(self):
+    def azure_credential_manager(self) -> StorageCredentialManager:
         return StorageCredentialManager(self.workspace_client)
 
     @cached_property
-    def service_principal_migration(self):
+    def service_principal_migration(self) -> ServicePrincipalMigration:
         return ServicePrincipalMigration(
             self.installation,
             self.workspace_client,
@@ -107,7 +108,7 @@ def service_principal_migration(self):
         )
 
     @cached_property
-    def external_locations_migration(self):
+    def external_locations_migration(self) -> AWSExternalLocationsMigration | ExternalLocationsMigration:
         if self.is_aws:
             return AWSExternalLocationsMigration(
                 self.workspace_client,
@@ -126,7 +127,7 @@ def external_locations_migration(self):
         raise NotImplementedError
 
     @cached_property
-    def aws_cli_run_command(self):
+    def aws_cli_run_command(self) -> Callable[[str | list[str]], tuple[int, str, str]]:
         # this is a convenience method for unit testing
         if not shutil.which("aws"):
             raise ValueError("Couldn't find AWS CLI in path. Please install the CLI from https://aws.amazon.com/cli/")
@@ -145,13 +146,13 @@ def aws_profile(self) -> str:
         return aws_profile
 
     @cached_property
-    def aws_resources(self):
+    def aws_resources(self) -> AWSResources:
         if not self.is_aws:
             raise NotImplementedError("AWS only")
         return AWSResources(self.aws_profile, self.aws_cli_run_command)
 
     @cached_property
-    def aws_resource_permissions(self):
+    def aws_resource_permissions(self) -> AWSResourcePermissions:
         return AWSResourcePermissions(
             self.installation,
             self.workspace_client,
@@ -161,7 +162,7 @@ def aws_resource_permissions(self):
         )
 
     @cached_property
-    def iam_role_migration(self):
+    def iam_role_migration(self) -> IamRoleMigration:
         return IamRoleMigration(
             self.installation,
             self.aws_resource_permissions,
@@ -169,7 +170,7 @@ def iam_role_migration(self):
         )
 
     @cached_property
-    def iam_role_creation(self):
+    def iam_role_creation(self) -> IamRoleCreation:
         return IamRoleCreation(
             self.installation,
             self.workspace_client,
@@ -200,11 +201,11 @@ def linter_context_factory(self, session_state: CurrentSessionState | None = Non
         return LinterContext(index, session_state)
 
     @cached_property
-    def local_file_migrator(self):
+    def local_file_migrator(self) -> LocalFileMigrator:
         return LocalFileMigrator(lambda: self.linter_context_factory(CurrentSessionState()))
 
     @cached_property
-    def local_code_linter(self):
+    def local_code_linter(self) -> LocalCodeLinter:
         session_state = CurrentSessionState()
         return LocalCodeLinter(
             self.notebook_loader,
diff --git a/src/databricks/labs/ucx/hive_metastore/locations.py b/src/databricks/labs/ucx/hive_metastore/locations.py
index 05802153b4..6ad6817f8e 100644
--- a/src/databricks/labs/ucx/hive_metastore/locations.py
+++ b/src/databricks/labs/ucx/hive_metastore/locations.py
@@ -54,10 +54,10 @@ class LocationTrie:
     tables: list[Table] = dataclasses.field(default_factory=list)
 
     @cached_property
-    def _path(self):
+    def _path(self) -> list[str]:
         """The path to traverse to get to the current node."""
         parts = []
-        current = self
+        current: LocationTrie | None = self
         while current:
             parts.append(current.key)
             current = current.parent
diff --git a/src/databricks/labs/ucx/hive_metastore/tables.py b/src/databricks/labs/ucx/hive_metastore/tables.py
index f935aada95..097faca778 100644
--- a/src/databricks/labs/ucx/hive_metastore/tables.py
+++ b/src/databricks/labs/ucx/hive_metastore/tables.py
@@ -4,7 +4,7 @@
 from collections.abc import Iterable, Iterator, Collection
 from dataclasses import dataclass
 from enum import Enum, auto
-from functools import partial, cached_property
+from functools import cached_property, partial
 
 import sqlglot
 from sqlglot import expressions
diff --git a/src/databricks/labs/ucx/install.py b/src/databricks/labs/ucx/install.py
index 812be2c22d..d2cc3a9561 100644
--- a/src/databricks/labs/ucx/install.py
+++ b/src/databricks/labs/ucx/install.py
@@ -165,15 +165,15 @@ def __init__(
         self._tasks = tasks if tasks else Workflows.all().tasks()
 
     @cached_property
-    def upgrades(self):
+    def upgrades(self) -> Upgrades:
         return Upgrades(self.product_info, self.installation)
 
     @cached_property
-    def policy_installer(self):
+    def policy_installer(self) -> ClusterPolicyInstaller:
         return ClusterPolicyInstaller(self.installation, self.workspace_client, self.prompts)
 
     @cached_property
-    def installation(self):
+    def installation(self) -> Installation:
         try:
             return self.product_info.current_installation(self.workspace_client)
         except NotFound:
@@ -820,12 +820,13 @@ def join_collection(self, workspace_ids: list[int], join_on_install: bool = Fals
 
         account_client = self._get_safe_account_client()
         ctx = AccountContext(account_client)
-        try:
+        try:  # pylint: disable=too-many-try-statements
             # if user is account admin list all the available workspace the user has admin access on.
             # This code is run if joining collection after installation or through cli
             accessible_workspaces = ctx.account_workspaces.get_accessible_workspaces()
             for workspace in accessible_workspaces:
-                ids_to_workspace[workspace.workspace_id] = workspace
+                if workspace.workspace_id is not None:
+                    ids_to_workspace[workspace.workspace_id] = workspace
             if join_on_install:
                 # if run as part of ucx installation allow user to select from the list to join
                 target_workspace = self._get_collection_workspace(accessible_workspaces, account_client)
diff --git a/src/databricks/labs/ucx/source_code/known.py b/src/databricks/labs/ucx/source_code/known.py
index 60a266b26d..4d08f746a8 100644
--- a/src/databricks/labs/ucx/source_code/known.py
+++ b/src/databricks/labs/ucx/source_code/known.py
@@ -8,6 +8,7 @@
 import re
 import sys
 from dataclasses import dataclass
+from email.message import Message
 from functools import cached_property
 from pathlib import Path
 
@@ -208,7 +209,7 @@ def module_paths(self) -> list[Path]:
         return files
 
     @cached_property
-    def _metadata(self):
+    def _metadata(self) -> Message:
         with Path(self._path, "METADATA").open(encoding=_DEFAULT_ENCODING) as f:
             return email.message_from_file(f)
 
diff --git a/src/databricks/labs/ucx/source_code/python_libraries.py b/src/databricks/labs/ucx/source_code/python_libraries.py
index f675362ed8..21e3738fe6 100644
--- a/src/databricks/labs/ucx/source_code/python_libraries.py
+++ b/src/databricks/labs/ucx/source_code/python_libraries.py
@@ -43,7 +43,7 @@ def register_library(self, path_lookup: PathLookup, *libraries: str) -> list[Dep
         return self._install_library(path_lookup, *libraries)
 
     @cached_property
-    def _temporary_virtual_environment(self):
+    def _temporary_virtual_environment(self) -> Path:
         # TODO: for `databricks labs ucx lint-local-code`, detect if we already have a virtual environment
         # and use that one. See Databricks CLI code for the labs command to see how to detect the virtual
         # environment. If we don't have a virtual environment, create a temporary one.
diff --git a/src/databricks/labs/ucx/workspace_access/generic.py b/src/databricks/labs/ucx/workspace_access/generic.py
index 0fd06db6d9..6945f22d73 100644
--- a/src/databricks/labs/ucx/workspace_access/generic.py
+++ b/src/databricks/labs/ucx/workspace_access/generic.py
@@ -397,7 +397,7 @@ def __repr__(self):
         return f"WorkspaceListing(start_path={self._start_path})"
 
 
-def models_listing(ws: WorkspaceClient, num_threads: int):
+def models_listing(ws: WorkspaceClient, num_threads: int | None) -> Callable[[], Iterator[ml.ModelDatabricks]]:
     def inner() -> Iterator[ml.ModelDatabricks]:
         tasks = []
         for model in ws.model_registry.list_models():
diff --git a/tests/integration/conftest.py b/tests/integration/conftest.py
index 2fc3f47b08..853257e134 100644
--- a/tests/integration/conftest.py
+++ b/tests/integration/conftest.py
@@ -26,12 +26,12 @@
 from databricks.sdk import AccountClient, WorkspaceClient
 from databricks.sdk.errors import NotFound
 from databricks.sdk.retries import retried
-from databricks.sdk.service import iam
+from databricks.sdk.service import iam, jobs
 from databricks.sdk.service.catalog import FunctionInfo, SchemaInfo, TableInfo
 from databricks.sdk.service.compute import ClusterSpec
 from databricks.sdk.service.dashboards import Dashboard as SDKDashboard
 from databricks.sdk.service.iam import Group
-from databricks.sdk.service.jobs import Task, SparkPythonTask
+from databricks.sdk.service.jobs import SparkPythonTask
 from databricks.sdk.service.sql import Dashboard, WidgetPosition, WidgetOptions, LegacyQuery
 
 from databricks.labs.ucx.__about__ import __version__
@@ -46,6 +46,7 @@
 from databricks.labs.ucx.config import WorkspaceConfig
 from databricks.labs.ucx.contexts.workspace_cli import WorkspaceContext
 from databricks.labs.ucx.contexts.workflow_task import RuntimeContext
+from databricks.labs.ucx.framework.tasks import Task
 from databricks.labs.ucx.hive_metastore import TablesCrawler
 from databricks.labs.ucx.hive_metastore.grants import Grant
 from databricks.labs.ucx.hive_metastore.locations import Mount, Mounts, ExternalLocation, ExternalLocations
@@ -436,7 +437,7 @@ def with_aws_storage_permissions(
         self.installation.save(uc_roles_mapping, filename=AWSResourcePermissions.UC_ROLES_FILE_NAME)
 
     @cached_property
-    def installation(self):
+    def installation(self) -> Installation:
         return MockInstallation()
 
     @cached_property
@@ -564,7 +565,7 @@ def config(self) -> WorkspaceConfig:
         )
 
     @cached_property
-    def tables_crawler(self) -> TablesCrawler:
+    def tables_crawler(self):
         """
         Returns a TablesCrawler instance with the tables that were created in the context.
         Overrides the FasterTableScanCrawler with TablesCrawler used as DBR is not available while running integration tests
@@ -658,14 +659,15 @@ def created_databases(self) -> list[str]:
         return list(created_databases)
 
     @cached_property
-    def created_groups(self):
+    def created_groups(self) -> list[str]:
         created_groups = []
         for group in self._groups:
-            created_groups.append(group.display_name)
+            if group.display_name is not None:
+                created_groups.append(group.display_name)
         return created_groups
 
     @cached_property
-    def azure_service_principal_crawler(self):
+    def azure_service_principal_crawler(self) -> StaticServicePrincipalCrawler:
         return StaticServicePrincipalCrawler(
             self._spn_infos,
             self.workspace_client,
@@ -674,7 +676,7 @@ def azure_service_principal_crawler(self):
         )
 
     @cached_property
-    def mounts_crawler(self):
+    def mounts_crawler(self) -> StaticMountCrawler:
         mount = Mount(
             f'/mnt/{self._env_or_skip("TEST_MOUNT_NAME")}/a', f'{self._env_or_skip("TEST_MOUNT_CONTAINER")}/a'
         )
@@ -686,7 +688,7 @@ def mounts_crawler(self):
         )
 
     @cached_property
-    def group_manager(self):
+    def group_manager(self) -> GroupManager:
         return GroupManager(
             self.sql_backend,
             self.workspace_client,
@@ -768,7 +770,7 @@ def save_locations(self) -> None:
 
 class MockLocalAzureCli(MockWorkspaceContext):
     @cached_property
-    def azure_cli_authenticated(self):
+    def azure_cli_authenticated(self) -> bool:
         if not self.is_azure:
             pytest.skip("Azure only")
         if self.connect_config.auth_type != "azure-cli":
@@ -788,7 +790,7 @@ def az_cli_ctx(ws, env_or_skip, make_catalog, make_schema, make_random, sql_back
 
 class MockLocalAwsCli(MockWorkspaceContext):
     @cached_property
-    def aws_cli_run_command(self):
+    def aws_cli_run_command(self) -> Callable[[str | list[str]], tuple[int, str, str]]:
         if not self.is_aws:
             pytest.skip("Aws only")
         if not shutil.which("aws"):
@@ -796,7 +798,7 @@ def aws_cli_run_command(self):
         return run_command
 
     @cached_property
-    def aws_profile(self):
+    def aws_profile(self) -> str:
         return self._env_or_skip("AWS_PROFILE")
 
 
@@ -884,7 +886,7 @@ def make_ucx_group(self, workspace_group_name=None, account_group_name=None, wai
         return ws_group, acc_group
 
     @cached_property
-    def running_clusters(self):
+    def running_clusters(self) -> tuple[str, str, str]:
         logger.debug("Waiting for clusters to start...")
         default_cluster_id = self._env_or_skip("TEST_DEFAULT_CLUSTER_ID")
         tacl_cluster_id = self._env_or_skip("TEST_LEGACY_TABLE_ACL_CLUSTER_ID")
@@ -902,15 +904,15 @@ def running_clusters(self):
         return default_cluster_id, tacl_cluster_id, table_migration_cluster_id
 
     @cached_property
-    def installation(self):
+    def installation(self) -> Installation:
         return Installation(self.workspace_client, self.product_info.product_name())
 
     @cached_property
-    def account_client(self):
+    def account_client(self) -> AccountClient:
         return AccountClient(product="ucx", product_version=__version__)
 
     @cached_property
-    def account_installer(self):
+    def account_installer(self) -> AccountInstaller:
         return AccountInstaller(self.account_client)
 
     @cached_property
@@ -918,7 +920,7 @@ def environ(self) -> dict[str, str]:
         return {**os.environ}
 
     @cached_property
-    def workspace_installer(self):
+    def workspace_installer(self) -> WorkspaceInstaller:
         return WorkspaceInstaller(
             self.workspace_client,
             self.environ,
@@ -929,7 +931,7 @@ def config_transform(self) -> Callable[[WorkspaceConfig], WorkspaceConfig]:
         return lambda wc: wc
 
     @cached_property
-    def include_object_permissions(self):
+    def include_object_permissions(self) -> None:
         return None
 
     @cached_property
@@ -956,15 +958,15 @@ def config(self) -> WorkspaceConfig:
         return workspace_config
 
     @cached_property
-    def product_info(self):
+    def product_info(self) -> ProductInfo:
         return ProductInfo.for_testing(WorkspaceConfig)
 
     @cached_property
-    def tasks(self):
+    def tasks(self) -> list[Task]:
         return Workflows.all().tasks()
 
     @cached_property
-    def workflows_deployment(self):
+    def workflows_deployment(self) -> WorkflowsDeployment:
         return WorkflowsDeployment(
             self.config,
             self.installation,
@@ -976,7 +978,7 @@ def workflows_deployment(self):
         )
 
     @cached_property
-    def workspace_installation(self):
+    def workspace_installation(self) -> WorkspaceInstallation:
         return WorkspaceInstallation(
             self.config,
             self.installation,
@@ -993,15 +995,15 @@ def progress_tracking_installation(self) -> ProgressTrackingInstallation:
         return ProgressTrackingInstallation(self.sql_backend, self.ucx_catalog)
 
     @cached_property
-    def extend_prompts(self):
+    def extend_prompts(self) -> dict[str, str]:
         return {}
 
     @cached_property
-    def renamed_group_prefix(self):
+    def renamed_group_prefix(self) -> str:
         return f"rename-{self.product_info.product_name()}-"
 
     @cached_property
-    def prompts(self):
+    def prompts(self) -> MockPrompts:
         return MockPrompts(
             {
                 r'Open job overview in your browser.*': 'no',
@@ -1262,7 +1264,7 @@ def create(installation, **_kwargs):
         file_name = f"dummy_{make_random(4)}_{watchdog_purge_suffix}"
         file_path = WorkspacePath(ws, installation.install_folder()) / file_name
         file_path.write_text("spark.read.parquet('dbfs://mnt/foo/bar')")
-        task = Task(
+        task = jobs.Task(
             task_key=make_random(4),
             description=make_random(4),
             new_cluster=ClusterSpec(