Order list_label results by issue count (descending) (#2974)

* Order list_label results by issue count (descending)

Sends orderBy: {field: ISSUE_COUNT, direction: DESC} on the GraphQL
labels query so the most-used labels (by issue count) are returned
first. ISSUE_COUNT is accepted by the GitHub GraphQL API but is not
part of the public schema docs or the githubv4 client library's
LabelOrderField constants, so it is defined locally.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Potential fix for pull request finding

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

* regen docs

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

Author: 3 people

pkg/github/__toolsnaps__/list_label.snap

@@ -4,7 +4,7 @@
     "readOnlyHint": true,
     "title": "List labels from a repository"
   },
-  "description": "List labels from a repository",
+  "description": "List labels from a repository, ordered by issue count (descending) so the most-used labels are returned first",
   "inputSchema": {
     "properties": {
       "owner": {

pkg/github/labels.go

@@ -17,6 +17,11 @@ import (
 	"github.com/shurcooL/githubv4"
 )
 
+// labelOrderFieldIssueCount orders labels by the number of issues they are assigned to.
+// It is not part of the githubv4.LabelOrderField constants shipped with the client library
+// (or GitHub's public GraphQL schema docs), but the API accepts it, so we define it locally.
+const labelOrderFieldIssueCount githubv4.LabelOrderField = "ISSUE_COUNT"
+
 // GetLabel retrieves a specific label by name from a GitHub repository
 func GetLabel(t translations.TranslationHelperFunc) inventory.ServerTool {
 	return NewTool(
@@ -129,9 +134,9 @@ func ListLabels(t translations.TranslationHelperFunc) inventory.ServerTool {
 		ToolsetLabels,
 		mcp.Tool{
 			Name:        "list_label",
-			Description: t("TOOL_LIST_LABEL_DESCRIPTION", "List labels from a repository"),
+			Description: t("TOOL_LIST_LABEL_DESCRIPTION", "List labels from a repository, ordered by issue count (descending) so the most-used labels are returned first"),
 			Annotations: &mcp.ToolAnnotations{
-				Title:        t("TOOL_LIST_LABEL_DESCRIPTION", "List labels from a repository"),
+				Title:        t("TOOL_LIST_LABEL_TITLE", "List labels from a repository"),
 				ReadOnlyHint: true,
 			},
 			InputSchema: &jsonschema.Schema{
@@ -176,13 +181,16 @@ func ListLabels(t translations.TranslationHelperFunc) inventory.ServerTool {
 							Description githubv4.String
 						}
 						TotalCount githubv4.Int
-					} `graphql:"labels(first: 100)"`
+					} `graphql:"labels(first: 100, orderBy: {field: $orderByField, direction: $orderByDirection})"`
 				} `graphql:"repository(owner: $owner, name: $repo)"`
 			}
 
 			vars := map[string]any{
 				"owner": githubv4.String(owner),
 				"repo":  githubv4.String(repo),
+				// Order labels by issue count (descending) so the most-used labels are returned first.
+				"orderByField":     labelOrderFieldIssueCount,
+				"orderByDirection": githubv4.OrderDirectionDesc,
 			}
 
 			if err := client.Query(ctx, &query, vars); err != nil {

pkg/github/labels_test.go

@@ -175,12 +175,14 @@ func TestListLabels(t *testing.T) {
 									Description githubv4.String
 								}
 								TotalCount githubv4.Int
-							} `graphql:"labels(first: 100)"`
+							} `graphql:"labels(first: 100, orderBy: {field: $orderByField, direction: $orderByDirection})"`
 						} `graphql:"repository(owner: $owner, name: $repo)"`
 					}{},
 					map[string]any{
-						"owner": githubv4.String("owner"),
-						"repo":  githubv4.String("repo"),
+						"owner":            githubv4.String("owner"),
+						"repo":             githubv4.String("repo"),
+						"orderByField":     labelOrderFieldIssueCount,
+						"orderByDirection": githubv4.OrderDirectionDesc,
 					},
 					githubv4mock.DataResponse(map[string]any{
 						"repository": map[string]any{