fix: add DestructiveHint and OpenWorldHint to label_write annotations

The label_write tool supports a delete method that permanently removes
a label and all its associations from every issue/PR in the repository.
However, it only set ReadOnlyHint: false and did not signal the
destructive nature of this operation to MCP clients.

Add DestructiveHint: true and OpenWorldHint: true to match the pattern
used by other destructive tools in the codebase (actions_run_trigger,
projects_write, discussion_comment_write, remove_sub_issue).

Fixes #2723

Author: axelray-dev

pkg/github/__toolsnaps__/label_write.snap

@@ -1,5 +1,7 @@
 {
   "annotations": {
+    "destructiveHint": true,
+    "openWorldHint": 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 +226,10 @@ 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),
+				OpenWorldHint:   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")
+	require.NotNil(t, tool.Annotations.DestructiveHint, "label_write tool should have DestructiveHint set")
+	assert.True(t, *tool.Annotations.DestructiveHint, "label_write tool should be marked as destructive")
 
 	tests := []struct {
 		name               string