From 8820ff6e4e3d2312ad8f684f228a9f232ca927ad Mon Sep 17 00:00:00 2001
From: K4bain <296577378+K4bain@users.noreply.github.com>
Date: Thu, 27 Aug 2026 21:20:10 +0500
Subject: [PATCH] fix(server): pass MCP description via instructions, not
 version
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Server(name, self.description) passed the description as the second
positional arg of mcp Server.__init__, which is version — so MCP
clients saw the server description as its version and no instructions
at all. Pass both explicitly: version from the FastAPI app version and
description as instructions.

Adopted from #317 (original patch by @syf2211).
---
 fastapi_mcp/server.py             | 6 +++++-
 tests/test_basic_functionality.py | 4 ++++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/fastapi_mcp/server.py b/fastapi_mcp/server.py
index bb751067..157acd8e 100644
--- a/fastapi_mcp/server.py
+++ b/fastapi_mcp/server.py
@@ -141,7 +141,11 @@ def setup_server(self) -> None:
         # Filter tools based on operation IDs and tags
         self.tools = self._filter_tools(all_tools, openapi_schema)
 
-        mcp_server: Server = Server(self.name, self.description)
+        mcp_server: Server = Server(
+            self.name,
+            version=self.fastapi.version,
+            instructions=self.description,
+        )
 
         @mcp_server.list_tools()
         async def handle_list_tools() -> List[types.Tool]:
diff --git a/tests/test_basic_functionality.py b/tests/test_basic_functionality.py
index 3557226e..9123934b 100644
--- a/tests/test_basic_functionality.py
+++ b/tests/test_basic_functionality.py
@@ -19,6 +19,10 @@ def test_create_mcp_server(simple_fastapi_app: FastAPI):
     assert len(mcp.tools) > 0, "Should have extracted tools from the app"
     assert len(mcp.operation_map) > 0, "Should have operation mapping"
 
+    assert mcp.server.version == simple_fastapi_app.version
+    assert mcp.server.instructions == "Test description"
+    assert mcp.server.version != mcp.server.instructions
+
     # Check that the operation map contains all expected operations from simple_app
     expected_operations = ["list_items", "get_item", "create_item", "update_item", "delete_item", "raise_error"]
     for op in expected_operations: