fix(labels): add DestructiveHint to label_write tool

The label_write delete method removes labels repository-wide but the tool
only advertised ReadOnlyHint:false. Set DestructiveHint:true so MCP clients
can warn before destructive label deletions, matching projects_write.

Fixes #2723

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: 2 people

pkg/github/__toolsnaps__/label_write.snap

@@ -1,5 +1,6 @@
 {
   "annotations": {
+    "destructiveHint": true,
     "title": "Write operations on repository labels"
   },
   "description": "Perform write operations on repository labels. To set labels on issues, use the 'update_issue' tool.",

pkg/github/labels.go

@@ -226,8 +226,9 @@ func LabelWrite(t translations.TranslationHelperFunc) inventory.ServerTool {
 			Name:        "label_write",
 			Description: t("TOOL_LABEL_WRITE_DESCRIPTION", "Perform write operations on repository labels. To set labels on issues, use the 'update_issue' tool."),
 			Annotations: &mcp.ToolAnnotations{
-				Title:        t("TOOL_LABEL_WRITE_TITLE", "Write operations on repository labels"),
-				ReadOnlyHint: false,
+				Title:           t("TOOL_LABEL_WRITE_TITLE", "Write operations on repository labels"),
+				ReadOnlyHint:    false,
+				DestructiveHint: jsonschema.Ptr(true),
 			},
 			InputSchema: &jsonschema.Schema{
 				Type: "object",

pkg/github/labels_test.go

@@ -247,6 +247,8 @@ func TestWriteLabel(t *testing.T) {
 	assert.Equal(t, "label_write", tool.Name)
 	assert.NotEmpty(t, tool.Description)
 	assert.False(t, tool.Annotations.ReadOnlyHint, "label_write tool should not be read-only")
+	assert.NotNil(t, tool.Annotations.DestructiveHint)
+	assert.True(t, *tool.Annotations.DestructiveHint, "label_write delete removes labels repository-wide")
 
 	tests := []struct {
 		name               string