fix(managers): clean up empty tenant scopes after last entry removal

Remove the inner dict from the outer storage when the last entry for a
tenant is deleted, preventing unbounded accumulation of empty dicts in
long-running servers with transient tenants.

Github-Issue:#8

Author: andylim-duo

src/mcp/server/mcpserver/prompts/manager.py

@@ -64,6 +64,8 @@ def remove_prompt(self, name: str, *, tenant_id: str | None = None) -> None:
         if name not in scope:
             raise ValueError(f"Unknown prompt: {name}")
         del scope[name]
+        if not scope and tenant_id in self._prompts:
+            del self._prompts[tenant_id]
 
     async def render_prompt(
         self,

src/mcp/server/mcpserver/resources/resource_manager.py

@@ -117,6 +117,8 @@ def remove_resource(self, uri: AnyUrl | str, *, tenant_id: str | None = None) ->
         if uri_str not in scope:
             raise ValueError(f"Unknown resource: {uri}")
         del scope[uri_str]
+        if not scope and tenant_id in self._resources:
+            del self._resources[tenant_id]
 
     async def get_resource(
         self,

src/mcp/server/mcpserver/tools/tool_manager.py

@@ -93,6 +93,8 @@ def remove_tool(self, name: str, *, tenant_id: str | None = None) -> None:
         if name not in scope:
             raise ToolError(f"Unknown tool: {name}")
         del scope[name]
+        if not scope and tenant_id in self._tools:
+            del self._tools[tenant_id]
 
     async def call_tool(
         self,

tests/server/mcpserver/test_multi_tenancy_managers.py

@@ -84,6 +84,8 @@ def my_tool() -> str:  # pragma: no cover
 
     assert manager.get_tool("my_tool", tenant_id="tenant-a") is None
     assert manager.get_tool("my_tool", tenant_id="tenant-b") is not None
+    # Empty tenant scope is cleaned up
+    assert "tenant-a" not in manager._tools
 
 
 def test_remove_tool_wrong_tenant_raises():
@@ -240,6 +242,8 @@ def test_remove_resource_with_tenant():
 
     assert len(manager.list_resources(tenant_id="tenant-a")) == 0
     assert len(manager.list_resources(tenant_id="tenant-b")) == 1
+    # Empty tenant scope is cleaned up
+    assert "tenant-a" not in manager._resources
 
 
 def test_remove_resource_wrong_tenant_raises():
@@ -330,6 +334,8 @@ def test_remove_prompt_with_tenant():
 
     assert manager.get_prompt("greet", tenant_id="tenant-a") is None
     assert manager.get_prompt("greet", tenant_id="tenant-b") is not None
+    # Empty tenant scope is cleaned up
+    assert "tenant-a" not in manager._prompts
 
 
 def test_remove_prompt_wrong_tenant_raises():