Fix server_version field in inspect manifest (#1383)

src/fastmcp/server/server.py

@@ -303,6 +303,10 @@ class FastMCP(Generic[LifespanResultT]):
     def instructions(self) -> str | None:
         return self._mcp_server.instructions
 
+    @property
+    def version(self) -> str | None:
+        return self._mcp_server.version
+
     async def run_async(
         self,
         transport: Transport | None = None,

src/fastmcp/utilities/inspect.py

@@ -9,6 +9,7 @@ from typing import Any
 from mcp.server.fastmcp import FastMCP as FastMCP1x
 
 import fastmcp
+from fastmcp import Client
 from fastmcp.server.server import FastMCP
 
 
@@ -71,7 +72,7 @@ class FastMCPInfo:
     instructions: str | None
     fastmcp_version: str
     mcp_version: str
-    server_version: str
+    server_version: str | None
     tools: list[ToolInfo]
     prompts: list[PromptInfo]
     resources: list[ResourceInfo]
@@ -170,7 +171,9 @@ async def inspect_fastmcp_v2(mcp: FastMCP[Any]) -> FastMCPInfo:
         instructions=mcp.instructions,
         fastmcp_version=fastmcp.__version__,
         mcp_version=importlib.metadata.version("mcp"),
-        server_version=fastmcp.__version__,  # v2.x uses FastMCP version
+        server_version=(
+            mcp.version if hasattr(mcp, "version") else mcp._mcp_server.version
+        ),
         tools=tool_infos,
         prompts=prompt_infos,
         resources=resource_infos,
@@ -179,7 +182,7 @@ async def inspect_fastmcp_v2(mcp: FastMCP[Any]) -> FastMCPInfo:
     )
 
 
-async def inspect_fastmcp_v1(mcp: Any) -> FastMCPInfo:
+async def inspect_fastmcp_v1(mcp: FastMCP1x) -> FastMCPInfo:
     """Extract information from a FastMCP v1.x instance using a Client.
 
     Args:
@@ -188,7 +191,6 @@ async def inspect_fastmcp_v1(mcp: Any) -> FastMCPInfo:
     Returns:
         FastMCPInfo dataclass containing the extracted information
     """
-    from fastmcp import Client
 
     # Use a client to interact with the FastMCP1x server
     async with Client(mcp) as client:
@@ -288,11 +290,11 @@ async def inspect_fastmcp_v1(mcp: Any) -> FastMCPInfo:
         }
 
         return FastMCPInfo(
-            name=mcp.name,
-            instructions=getattr(mcp, "instructions", None),
-            fastmcp_version=fastmcp.__version__,  # Report current fastmcp version
+            name=mcp._mcp_server.name,
+            instructions=mcp._mcp_server.instructions,
+            fastmcp_version=importlib.metadata.version("mcp"),
             mcp_version=importlib.metadata.version("mcp"),
-            server_version="1.0",  # FastMCP 1.x version
+            server_version=mcp._mcp_server.version,
             tools=tool_infos,
             prompts=prompt_infos,
             resources=resource_infos,
@@ -301,14 +303,7 @@ async def inspect_fastmcp_v1(mcp: Any) -> FastMCPInfo:
         )
 
 
-def _is_fastmcp_v1(mcp: Any) -> bool:
-    """Check if the given instance is a FastMCP v1.x instance."""
-
-    # Check if it's an instance of FastMCP1x and not FastMCP2
-    return isinstance(mcp, FastMCP1x) and not isinstance(mcp, FastMCP)
-
-
-async def inspect_fastmcp(mcp: FastMCP[Any] | Any) -> FastMCPInfo:
+async def inspect_fastmcp(mcp: FastMCP[Any] | FastMCP1x) -> FastMCPInfo:
     """Extract information from a FastMCP instance into a dataclass.
 
     This function automatically detects whether the instance is FastMCP v1.x or v2.x
@@ -320,7 +315,7 @@ async def inspect_fastmcp(mcp: FastMCP[Any] | Any) -> FastMCPInfo:
     Returns:
         FastMCPInfo dataclass containing the extracted information
     """
-    if _is_fastmcp_v1(mcp):
+    if isinstance(mcp, FastMCP1x):
         return await inspect_fastmcp_v1(mcp)
     else:
         return await inspect_fastmcp_v2(mcp)

tests/utilities/test_inspect.py

@@ -1,6 +1,7 @@
 """Tests for the inspect.py module."""
 
-# Import FastMCP1x for testing (always available since mcp is a dependency)
+import importlib.metadata
+
 from mcp.server.fastmcp import FastMCP as FastMCP1x
 
 import fastmcp
@@ -8,7 +9,6 @@ from fastmcp import Client, FastMCP
 from fastmcp.utilities.inspect import (
     FastMCPInfo,
     ToolInfo,
-    _is_fastmcp_v1,
     inspect_fastmcp,
     inspect_fastmcp_v1,
 )
@@ -67,15 +67,15 @@ class TestGetFastMCPInfo:
 
     async def test_empty_server(self):
         """Test get_fastmcp_info with an empty server."""
-        mcp = FastMCP("EmptyServer", instructions="Empty server for testing")
+        mcp = FastMCP("EmptyServer")
 
         info = await inspect_fastmcp(mcp)
 
         assert info.name == "EmptyServer"
-        assert info.instructions == "Empty server for testing"
+        assert info.instructions is None
         assert info.fastmcp_version == fastmcp.__version__
-        assert info.mcp_version is not None
-        assert info.server_version == fastmcp.__version__  # v2.x uses FastMCP version
+        assert info.mcp_version == importlib.metadata.version("mcp")
+        assert info.server_version is None
         assert info.tools == []
         assert info.prompts == []
         assert info.resources == []
@@ -85,6 +85,18 @@ class TestGetFastMCPInfo:
         assert "prompts" in info.capabilities
         assert "logging" in info.capabilities
 
+    async def test_server_with_instructions(self):
+        """Test get_fastmcp_info with a server that has instructions."""
+        mcp = FastMCP("InstructionsServer", instructions="Test instructions")
+        info = await inspect_fastmcp(mcp)
+        assert info.instructions == "Test instructions"
+
+    async def test_server_with_version(self):
+        """Test get_fastmcp_info with a server that has a version."""
+        mcp = FastMCP("VersionServer", version="1.2.3")
+        info = await inspect_fastmcp(mcp)
+        assert info.server_version == "1.2.3"
+
     async def test_server_with_tools(self):
         """Test get_fastmcp_info with a server that has tools."""
         mcp = FastMCP("ToolServer")
@@ -246,14 +258,6 @@ class TestGetFastMCPInfo:
 class TestFastMCP1xCompatibility:
     """Tests for FastMCP 1.x compatibility."""
 
-    async def test_fastmcp1x_detection(self):
-        """Test that FastMCP1x instances are correctly detected."""
-        mcp1x = FastMCP1x("Test1x")
-        mcp2x = FastMCP("Test2x")
-
-        assert _is_fastmcp_v1(mcp1x) is True
-        assert _is_fastmcp_v1(mcp2x) is False
-
     async def test_fastmcp1x_empty_server(self):
         """Test get_fastmcp_info_v1 with an empty FastMCP1x server."""
         mcp = FastMCP1x("Test1x")
@@ -262,9 +266,9 @@ class TestFastMCP1xCompatibility:
 
         assert info.name == "Test1x"
         assert info.instructions is None
-        assert info.fastmcp_version == fastmcp.__version__
-        assert info.mcp_version is not None
-        assert info.server_version == "1.0"  # v1.x servers use "1.0"
+        assert info.fastmcp_version == importlib.metadata.version("mcp")
+        assert info.mcp_version == importlib.metadata.version("mcp")
+        assert info.server_version is None
         assert info.tools == []
         assert info.prompts == []
         assert info.resources == []
@@ -380,8 +384,8 @@ class TestFastMCP1xCompatibility:
         assert "tool2x" in tool2x_names
 
         # Check server versions
-        assert info1x.server_version == "1.0"
-        assert info2x.server_version == fastmcp.__version__
+        assert info1x.server_version is None
+        assert info2x.server_version is None
 
         # No templates added in these tests
         assert len(info1x.templates) == 0