diff --git a/internal/mcp/server.go b/internal/mcp/server.go
index 23209f7..7db44d9 100644
--- a/internal/mcp/server.go
+++ b/internal/mcp/server.go
@@ -9,7 +9,7 @@ import (
 )
 
 const (
-	ProtocolVersion    = "2025-06-18"
+	ProtocolVersion    = "2025-03-26"
 	maxRequestBodyBytes = 1 << 20 // 1 MiB
 )
 
diff --git a/internal/mcp/server_test.go b/internal/mcp/server_test.go
index 7088d98..15f15fe 100644
--- a/internal/mcp/server_test.go
+++ b/internal/mcp/server_test.go
@@ -52,7 +52,7 @@ func TestInitialize(t *testing.T) {
 	var resp map[string]any
 	require.NoError(t, json.Unmarshal(rr.Body.Bytes(), &resp))
 	result := resp["result"].(map[string]any)
-	assert.Equal(t, "2025-06-18", result["protocolVersion"])
+	assert.Equal(t, mcp.ProtocolVersion, result["protocolVersion"])
 	si := result["serverInfo"].(map[string]any)
 	assert.Equal(t, "gitea-mcp", si["name"])
 }