feat(pullrequests): add labels support to create_pull_request tool

Add optional 'labels' parameter to the create_pull_request tool,
enabling users to apply labels during PR creation.

Since the GitHub REST API doesn't support labels in the PR creation
endpoint, labels are applied in a second step via the Issues API
(POST /repos/{owner}/{repo}/issues/{issue_number}/labels).

Changes:
- Add 'labels' array property to CreatePullRequest InputSchema
- Add post-creation AddLabelsToIssue call in the handler
- Add labels input field to pr-write MCP App UI
- Add test cases for label success and failure scenarios
- Update toolsnap snapshot and README documentation

Author: “yashdesai30”

README.md

@@ -1065,6 +1065,7 @@ The following sets of tools are available:
   - `body`: PR description (string, optional)
   - `draft`: Create as draft PR (boolean, optional)
   - `head`: Branch containing changes (string, required)
+  - `labels`: Labels to apply to this pull request (string[], optional)
   - `maintainer_can_modify`: Allow maintainer edits (boolean, optional)
   - `owner`: Repository owner (string, required)
   - `repo`: Repository name (string, required)

pkg/github/__toolsnaps__/create_pull_request.snap

@@ -30,6 +30,13 @@
         "description": "Branch containing changes",
         "type": "string"
       },
+      "labels": {
+        "description": "Labels to apply to this pull request",
+        "items": {
+          "type": "string"
+        },
+        "type": "array"
+      },
       "maintainer_can_modify": {
         "description": "Allow maintainer edits",
         "type": "boolean"

pkg/github/helper_test.go

@@ -59,6 +59,7 @@ const (
 	PostReposIssuesByOwnerByRepo                                = "POST /repos/{owner}/{repo}/issues"
 	PostReposIssuesCommentsByOwnerByRepoByIssueNumber           = "POST /repos/{owner}/{repo}/issues/{issue_number}/comments"
 	PatchReposIssuesByOwnerByRepoByIssueNumber                  = "PATCH /repos/{owner}/{repo}/issues/{issue_number}"
+	PostReposIssuesLabelsByOwnerByRepoByIssueNumber             = "POST /repos/{owner}/{repo}/issues/{issue_number}/labels"
 	GetReposIssuesSubIssuesByOwnerByRepoByIssueNumber           = "GET /repos/{owner}/{repo}/issues/{issue_number}/sub_issues"
 	PostReposIssuesSubIssuesByOwnerByRepoByIssueNumber          = "POST /repos/{owner}/{repo}/issues/{issue_number}/sub_issues"
 	DeleteReposIssuesSubIssueByOwnerByRepoByIssueNumber         = "DELETE /repos/{owner}/{repo}/issues/{issue_number}/sub_issue"

pkg/github/pullrequests.go

@@ -586,6 +586,11 @@ func CreatePullRequest(t translations.TranslationHelperFunc) inventory.ServerToo
 						Type:        "boolean",
 						Description: "Allow maintainer edits",
 					},
+					"labels": {
+						Type:        "array",
+						Items:       &jsonschema.Schema{Type: "string"},
+						Description: "Labels to apply to this pull request",
+					},
 				},
 				Required: []string{"owner", "repo", "title", "head", "base"},
 			},
@@ -648,6 +653,11 @@ func CreatePullRequest(t translations.TranslationHelperFunc) inventory.ServerToo
 				return utils.NewToolResultError(err.Error()), nil, nil
 			}
 
+			labels, err := OptionalStringArrayParam(args, "labels")
+			if err != nil {
+				return utils.NewToolResultError(err.Error()), nil, nil
+			}
+
 			newPR := &github.NewPullRequest{
 				Title: github.Ptr(title),
 				Head:  github.Ptr(head),
@@ -683,6 +693,21 @@ func CreatePullRequest(t translations.TranslationHelperFunc) inventory.ServerToo
 				return ghErrors.NewGitHubAPIStatusErrorResponse(ctx, "failed to create pull request", resp, bodyBytes), nil, nil
 			}
 
+			// Add labels if provided
+			if len(labels) > 0 {
+				_, labelsResp, labelsErr := client.Issues.AddLabelsToIssue(ctx, owner, repo, pr.GetNumber(), labels)
+				if labelsErr != nil {
+					return ghErrors.NewGitHubAPIErrorResponse(ctx,
+						fmt.Sprintf("pull request created (#%d) but failed to add labels", pr.GetNumber()),
+						labelsResp,
+						labelsErr,
+					), nil, nil
+				}
+				if labelsResp != nil {
+					_ = labelsResp.Body.Close()
+				}
+			}
+
 			// Return minimal response with just essential information
 			minimalResponse := MinimalResponse{
 				ID:  fmt.Sprintf("%d", pr.GetID()),

pkg/github/pullrequests_test.go

@@ -2181,6 +2181,7 @@ func Test_CreatePullRequest(t *testing.T) {
 	assert.Contains(t, schema.Properties, "base")
 	assert.Contains(t, schema.Properties, "draft")
 	assert.Contains(t, schema.Properties, "maintainer_can_modify")
+	assert.Contains(t, schema.Properties, "labels")
 	assert.ElementsMatch(t, schema.Required, []string{"owner", "repo", "title", "head", "base"})
 
 	// Setup mock PR for success case
@@ -2269,6 +2270,46 @@ func Test_CreatePullRequest(t *testing.T) {
 			expectError:    true,
 			expectedErrMsg: "failed to create pull request",
 		},
+		{
+			name: "successful PR creation with labels",
+			mockedClient: MockHTTPClientWithHandlers(map[string]http.HandlerFunc{
+				PostReposPullsByOwnerByRepo: mockResponse(t, http.StatusCreated, mockPR),
+				PostReposIssuesLabelsByOwnerByRepoByIssueNumber: mockResponse(t, http.StatusOK, []*github.Label{
+					{Name: github.Ptr("bug")},
+					{Name: github.Ptr("enhancement")},
+				}),
+			}),
+			requestArgs: map[string]any{
+				"owner":  "owner",
+				"repo":   "repo",
+				"title":  "Test PR",
+				"head":   "feature-branch",
+				"base":   "main",
+				"labels": []any{"bug", "enhancement"},
+			},
+			expectError: false,
+			expectedPR:  mockPR,
+		},
+		{
+			name: "labels addition fails after PR creation",
+			mockedClient: MockHTTPClientWithHandlers(map[string]http.HandlerFunc{
+				PostReposPullsByOwnerByRepo: mockResponse(t, http.StatusCreated, mockPR),
+				PostReposIssuesLabelsByOwnerByRepoByIssueNumber: http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+					w.WriteHeader(http.StatusNotFound)
+					_, _ = w.Write([]byte(`{"message": "Label does not exist"}`))
+				}),
+			}),
+			requestArgs: map[string]any{
+				"owner":  "owner",
+				"repo":   "repo",
+				"title":  "Test PR",
+				"head":   "feature-branch",
+				"base":   "main",
+				"labels": []any{"nonexistent-label"},
+			},
+			expectError:    true,
+			expectedErrMsg: "failed to add labels",
+		},
 	}
 
 	for _, tc := range tests {

ui/src/apps/pr-write/App.tsx

@@ -119,6 +119,7 @@ function SuccessView({
 function CreatePRApp() {
   const [title, setTitle] = useState("");
   const [body, setBody] = useState("");
+  const [labels, setLabels] = useState("");
   const [isSubmitting, setIsSubmitting] = useState(false);
   const [error, setError] = useState<string | null>(null);
   const [successPR, setSuccessPR] = useState<PRResult | null>(null);
@@ -140,6 +141,10 @@ function CreatePRApp() {
   useEffect(() => {
     if (toolInput?.title) setTitle(toolInput.title as string);
     if (toolInput?.body) setBody(toolInput.body as string);
+    if (toolInput?.labels) {
+      const labelsArr = toolInput.labels as string[];
+      setLabels(labelsArr.join(", "));
+    }
     if (toolInput?.draft) setIsDraft(toolInput.draft as boolean);
     if (toolInput?.maintainer_can_modify !== undefined) {
       setMaintainerCanModify(toolInput.maintainer_can_modify as boolean);
@@ -154,6 +159,8 @@ function CreatePRApp() {
     setError(null);
     setSubmittedTitle(title);
 
+    const labelsArray = labels.split(",").map(l => l.trim()).filter(l => l !== "");
+
     try {
       const result = await callTool("create_pull_request", {
         owner, repo,
@@ -163,6 +170,7 @@ function CreatePRApp() {
         base,
         draft: isDraft,
         maintainer_can_modify: maintainerCanModify,
+        labels: labelsArray,
         _ui_submitted: true
       });
 
@@ -182,7 +190,7 @@ function CreatePRApp() {
     } finally {
       setIsSubmitting(false);
     }
-  }, [title, body, owner, repo, head, base, isDraft, maintainerCanModify, callTool]);
+  }, [title, body, labels, owner, repo, head, base, isDraft, maintainerCanModify, callTool]);
 
   if (successPR) {
     return (
@@ -260,6 +268,18 @@ function CreatePRApp() {
           />
         </FormControl>
 
+        {/* Labels */}
+        <FormControl sx={{ mb: 3 }}>
+          <FormControl.Label sx={{ fontWeight: "semibold" }}>Labels</FormControl.Label>
+          <TextInput
+            value={labels}
+            onChange={(e) => setLabels(e.target.value)}
+            placeholder="bug, enhancement, help wanted (comma separated)"
+            block
+            contrast
+          />
+        </FormControl>
+
         {/* Description */}
         <Box sx={{ mb: 3 }}>
           <Text as="label" sx={{ fontWeight: "semibold", fontSize: 1, display: "block", mb: 2 }}>