Add meta support to tool transformation utilities (#1295)

tests/tools/test_tool_transform.py

@@ -13,7 +13,11 @@ from fastmcp.client.client import Client
 from fastmcp.exceptions import ToolError
 from fastmcp.tools import Tool, forward, forward_raw
 from fastmcp.tools.tool import FunctionTool, ToolResult
-from fastmcp.tools.tool_transform import ArgTransform, TransformedTool
+from fastmcp.tools.tool_transform import (
+    ArgTransform,
+    ToolTransformConfig,
+    TransformedTool,
+)
 
 
 def get_property(tool: Tool, name: str) -> dict[str, Any]:
@@ -1428,3 +1432,65 @@ def test_transform_adds_description_to_none(sample_tool_no_title):
     """Test that transformed tools can add description when parent has None."""
     transformed = Tool.from_tool(sample_tool_no_title, description="Added description")
     assert transformed.description == "Added description"
+
+
+# Meta transformation tests
+def test_transform_inherits_meta(sample_tool):
+    """Test that transformed tools inherit meta when none specified."""
+    sample_tool.meta = {"original": True, "version": "1.0"}
+    transformed = Tool.from_tool(sample_tool)
+    assert transformed.meta == {"original": True, "version": "1.0"}
+
+
+def test_transform_overrides_meta(sample_tool):
+    """Test that transformed tools can override meta."""
+    sample_tool.meta = {"original": True, "version": "1.0"}
+    transformed = Tool.from_tool(sample_tool, meta={"custom": True, "priority": "high"})
+    assert transformed.meta == {"custom": True, "priority": "high"}
+
+
+def test_transform_sets_meta_to_none(sample_tool):
+    """Test that transformed tools can explicitly set meta to None."""
+    sample_tool.meta = {"original": True, "version": "1.0"}
+    transformed = Tool.from_tool(sample_tool, meta=None)
+    assert transformed.meta is None
+
+
+def test_transform_inherits_none_meta(sample_tool_no_title):
+    """Test that transformed tools inherit None meta."""
+    sample_tool_no_title.meta = None
+    transformed = Tool.from_tool(sample_tool_no_title)
+    assert transformed.meta is None
+
+
+def test_transform_adds_meta_to_none(sample_tool_no_title):
+    """Test that transformed tools can add meta when parent has None."""
+    sample_tool_no_title.meta = None
+    transformed = Tool.from_tool(sample_tool_no_title, meta={"added": True})
+    assert transformed.meta == {"added": True}
+
+
+def test_tool_transform_config_inherits_meta(sample_tool):
+    """Test that ToolTransformConfig inherits meta when unset."""
+    sample_tool.meta = {"original": True, "version": "1.0"}
+    config = ToolTransformConfig(name="config_tool")
+    transformed = config.apply(sample_tool)
+    assert transformed.meta == {"original": True, "version": "1.0"}
+
+
+def test_tool_transform_config_overrides_meta(sample_tool):
+    """Test that ToolTransformConfig can override meta."""
+    sample_tool.meta = {"original": True, "version": "1.0"}
+    config = ToolTransformConfig(
+        name="config_tool", meta={"config": True, "priority": "high"}
+    )
+    transformed = config.apply(sample_tool)
+    assert transformed.meta == {"config": True, "priority": "high"}
+
+
+def test_tool_transform_config_removes_meta(sample_tool):
+    """Test that ToolTransformConfig can remove meta with None."""
+    sample_tool.meta = {"original": True, "version": "1.0"}
+    config = ToolTransformConfig(name="config_tool", meta=None)
+    transformed = config.apply(sample_tool)
+    assert transformed.meta is None