Expose reactions through default comment tools

Keep the standalone reaction tools behind granular feature flags to avoid expanding the default tool count. Add optional reaction support to the existing issue comment and pull request comment reply tools, requiring at least one of body or reaction.

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

Author: SamMorrowDrums

README.md

@@ -841,23 +841,10 @@ The following sets of tools are available:
 
 - **add_issue_comment** - Add comment to issue or pull request
   - **Required OAuth Scopes**: `repo`
-  - `body`: Comment content (string, required)
-  - `issue_number`: Issue number to comment on (number, required)
+  - `body`: Comment content. Required unless reaction is provided. (string, optional)
+  - `issue_number`: Issue number to comment on or react to (number, required)
   - `owner`: Repository owner (string, required)
-  - `repo`: Repository name (string, required)
-
-- **add_issue_comment_reaction** - Add Reaction to Issue or Pull Request Comment
-  - **Required OAuth Scopes**: `repo`
-  - `comment_id`: The issue comment ID (number, required)
-  - `content`: The emoji reaction type (string, required)
-  - `owner`: Repository owner (username or organization) (string, required)
-  - `repo`: Repository name (string, required)
-
-- **add_issue_reaction** - Add Reaction to Issue or Pull Request
-  - **Required OAuth Scopes**: `repo`
-  - `content`: The emoji reaction type (string, required)
-  - `issue_number`: The issue number (number, required)
-  - `owner`: Repository owner (username or organization) (string, required)
+  - `reaction`: Emoji reaction to add. Required unless body is provided. (string, optional)
   - `repo`: Repository name (string, required)
 
 - **get_label** - Get a specific label from a repository
@@ -1109,19 +1096,13 @@ The following sets of tools are available:
   - `startSide`: For multi-line comments, the starting side of the diff that the comment applies to. LEFT indicates the previous state, RIGHT indicates the new state (string, optional)
   - `subjectType`: The level at which the comment is targeted (string, required)
 
-- **add_pull_request_review_comment_reaction** - Add Pull Request Review Comment Reaction
-  - **Required OAuth Scopes**: `repo`
-  - `comment_id`: The pull request review comment ID (number, required)
-  - `content`: The emoji reaction type (string, required)
-  - `owner`: Repository owner (username or organization) (string, required)
-  - `repo`: Repository name (string, required)
-
 - **add_reply_to_pull_request_comment** - Add reply to pull request comment
   - **Required OAuth Scopes**: `repo`
-  - `body`: The text of the reply (string, required)
-  - `commentId`: The ID of the comment to reply to (number, required)
+  - `body`: The text of the reply. Required unless reaction is provided. (string, optional)
+  - `commentId`: The ID of the comment to reply or react to (number, required)
   - `owner`: Repository owner (string, required)
-  - `pullNumber`: Pull request number (number, required)
+  - `pullNumber`: Pull request number. Required when body is provided. (number, optional)
+  - `reaction`: Emoji reaction to add. Required unless body is provided. (string, optional)
   - `repo`: Repository name (string, required)
 
 - **create_pull_request** - Open new pull request

docs/feature-flags.md

@@ -98,6 +98,20 @@ runtime behavior (such as output formatting) won't appear here.
 
 ### `issues_granular`
 
+- **add_issue_comment_reaction** - Add Reaction to Issue or Pull Request Comment
+  - **Required OAuth Scopes**: `repo`
+  - `comment_id`: The issue comment ID (number, required)
+  - `content`: The emoji reaction type (string, required)
+  - `owner`: Repository owner (username or organization) (string, required)
+  - `repo`: Repository name (string, required)
+
+- **add_issue_reaction** - Add Reaction to Issue or Pull Request
+  - **Required OAuth Scopes**: `repo`
+  - `content`: The emoji reaction type (string, required)
+  - `issue_number`: The issue number (number, required)
+  - `owner`: Repository owner (username or organization) (string, required)
+  - `repo`: Repository name (string, required)
+
 - **add_sub_issue** - Add Sub-Issue
   - **Required OAuth Scopes**: `repo`
   - `issue_number`: The parent issue number (number, required)
@@ -204,6 +218,13 @@ runtime behavior (such as output formatting) won't appear here.
   - `startSide`: The start side of a multi-line comment (optional) (string, optional)
   - `subjectType`: The subject type of the comment (string, required)
 
+- **add_pull_request_review_comment_reaction** - Add Pull Request Review Comment Reaction
+  - **Required OAuth Scopes**: `repo`
+  - `comment_id`: The pull request review comment ID (number, required)
+  - `content`: The emoji reaction type (string, required)
+  - `owner`: Repository owner (username or organization) (string, required)
+  - `repo`: Repository name (string, required)
+
 - **create_pull_request_review** - Create Pull Request Review
   - **Required OAuth Scopes**: `repo`
   - `body`: The review body text (optional) (string, optional)

pkg/github/__toolsnaps__/add_issue_comment.snap

@@ -2,21 +2,35 @@
   "annotations": {
     "title": "Add comment to issue or pull request"
   },
-  "description": "Add a comment to a specific issue in a GitHub repository. Use this tool to add comments to pull requests as well (in this case pass pull request number as issue_number), but only if user is not asking specifically to add review comments.",
+  "description": "Add a comment and/or reaction to a specific issue in a GitHub repository. Use this tool with pull requests as well (in this case pass pull request number as issue_number), but only if user is not asking specifically to add or react to review comments. At least one of body or reaction is required.",
   "inputSchema": {
     "properties": {
       "body": {
-        "description": "Comment content",
+        "description": "Comment content. Required unless reaction is provided.",
         "type": "string"
       },
       "issue_number": {
-        "description": "Issue number to comment on",
+        "description": "Issue number to comment on or react to",
         "type": "number"
       },
       "owner": {
         "description": "Repository owner",
         "type": "string"
       },
+      "reaction": {
+        "description": "Emoji reaction to add. Required unless body is provided.",
+        "enum": [
+          "+1",
+          "-1",
+          "laugh",
+          "confused",
+          "heart",
+          "hooray",
+          "rocket",
+          "eyes"
+        ],
+        "type": "string"
+      },
       "repo": {
         "description": "Repository name",
         "type": "string"
@@ -25,8 +39,7 @@
     "required": [
       "owner",
       "repo",
-      "issue_number",
-      "body"
+      "issue_number"
     ],
     "type": "object"
   },

pkg/github/__toolsnaps__/add_reply_to_pull_request_comment.snap

@@ -2,25 +2,39 @@
   "annotations": {
     "title": "Add reply to pull request comment"
   },
-  "description": "Add a reply to an existing pull request comment. This creates a new comment that is linked as a reply to the specified comment.",
+  "description": "Add a reply and/or reaction to an existing pull request comment. This can create a new comment linked as a reply to the specified comment, add an emoji reaction to the specified comment, or do both. At least one of body or reaction is required.",
   "inputSchema": {
     "properties": {
       "body": {
-        "description": "The text of the reply",
+        "description": "The text of the reply. Required unless reaction is provided.",
         "type": "string"
       },
       "commentId": {
-        "description": "The ID of the comment to reply to",
+        "description": "The ID of the comment to reply or react to",
         "type": "number"
       },
       "owner": {
         "description": "Repository owner",
         "type": "string"
       },
       "pullNumber": {
-        "description": "Pull request number",
+        "description": "Pull request number. Required when body is provided.",
         "type": "number"
       },
+      "reaction": {
+        "description": "Emoji reaction to add. Required unless body is provided.",
+        "enum": [
+          "+1",
+          "-1",
+          "laugh",
+          "confused",
+          "heart",
+          "hooray",
+          "rocket",
+          "eyes"
+        ],
+        "type": "string"
+      },
       "repo": {
         "description": "Repository name",
         "type": "string"
@@ -29,9 +43,7 @@
     "required": [
       "owner",
       "repo",
-      "pullNumber",
-      "commentId",
-      "body"
+      "commentId"
     ],
     "type": "object"
   },

pkg/github/granular_tools_test.go

@@ -90,6 +90,8 @@ func TestIssuesGranularToolset(t *testing.T) {
 			"remove_sub_issue",
 			"reprioritize_sub_issue",
 			"set_issue_fields",
+			"add_issue_reaction",
+			"add_issue_comment_reaction",
 		}
 		for _, name := range expected {
 			assert.Contains(t, toolNames, name)
@@ -125,6 +127,7 @@ func TestPullRequestsGranularToolset(t *testing.T) {
 			"add_pull_request_review_comment",
 			"resolve_review_thread",
 			"unresolve_review_thread",
+			"add_pull_request_review_comment_reaction",
 		}
 		for _, name := range expected {
 			assert.Contains(t, toolNames, name)

pkg/github/issues.go

@@ -1051,13 +1051,13 @@ func ListIssueTypes(t translations.TranslationHelperFunc) inventory.ServerTool {
 		})
 }
 
-// AddIssueComment creates a tool to add a comment to an issue.
+// AddIssueComment creates a tool to add a comment or reaction to an issue.
 func AddIssueComment(t translations.TranslationHelperFunc) inventory.ServerTool {
 	return NewTool(
 		ToolsetMetadataIssues,
 		mcp.Tool{
 			Name:        "add_issue_comment",
-			Description: t("TOOL_ADD_ISSUE_COMMENT_DESCRIPTION", "Add a comment to a specific issue in a GitHub repository. Use this tool to add comments to pull requests as well (in this case pass pull request number as issue_number), but only if user is not asking specifically to add review comments."),
+			Description: t("TOOL_ADD_ISSUE_COMMENT_DESCRIPTION", "Add a comment and/or reaction to a specific issue in a GitHub repository. Use this tool with pull requests as well (in this case pass pull request number as issue_number), but only if user is not asking specifically to add or react to review comments. At least one of body or reaction is required."),
 			Annotations: &mcp.ToolAnnotations{
 				Title:        t("TOOL_ADD_ISSUE_COMMENT_USER_TITLE", "Add comment to issue or pull request"),
 				ReadOnlyHint: false,
@@ -1075,14 +1075,19 @@ func AddIssueComment(t translations.TranslationHelperFunc) inventory.ServerTool
 					},
 					"issue_number": {
 						Type:        "number",
-						Description: "Issue number to comment on",
+						Description: "Issue number to comment on or react to",
 					},
 					"body": {
 						Type:        "string",
-						Description: "Comment content",
+						Description: "Comment content. Required unless reaction is provided.",
+					},
+					"reaction": {
+						Type:        "string",
+						Description: "Emoji reaction to add. Required unless body is provided.",
+						Enum:        []any{"+1", "-1", "laugh", "confused", "heart", "hooray", "rocket", "eyes"},
 					},
 				},
-				Required: []string{"owner", "repo", "issue_number", "body"},
+				Required: []string{"owner", "repo", "issue_number"},
 			},
 		},
 		[]scopes.Scope{scopes.Repo},
@@ -1099,39 +1104,82 @@ func AddIssueComment(t translations.TranslationHelperFunc) inventory.ServerTool
 			if err != nil {
 				return utils.NewToolResultError(err.Error()), nil, nil
 			}
-			body, err := RequiredParam[string](args, "body")
+			body, hasBody, err := OptionalParamOK[string](args, "body")
 			if err != nil {
 				return utils.NewToolResultError(err.Error()), nil, nil
 			}
-
-			comment := &github.IssueComment{
-				Body: github.Ptr(body),
+			reactionContent, hasReaction, err := OptionalParamOK[string](args, "reaction")
+			if err != nil {
+				return utils.NewToolResultError(err.Error()), nil, nil
+			}
+			if !hasBody && !hasReaction {
+				return utils.NewToolResultError("at least one of body or reaction is required"), nil, nil
+			}
+			if hasBody && body == "" {
+				return utils.NewToolResultError("body cannot be empty when provided"), nil, nil
+			}
+			if hasReaction && reactionContent == "" {
+				return utils.NewToolResultError("reaction cannot be empty when provided"), nil, nil
 			}
 
 			client, err := deps.GetClient(ctx)
 			if err != nil {
 				return utils.NewToolResultErrorFromErr("failed to get GitHub client", err), nil, nil
 			}
-			createdComment, resp, err := client.Issues.CreateComment(ctx, owner, repo, issueNumber, comment)
-			if err != nil {
-				return utils.NewToolResultErrorFromErr("failed to create comment", err), nil, nil
+
+			var commentResponse *MinimalResponse
+			if hasBody {
+				comment := &github.IssueComment{
+					Body: github.Ptr(body),
+				}
+				createdComment, resp, err := client.Issues.CreateComment(ctx, owner, repo, issueNumber, comment)
+				if err != nil {
+					return utils.NewToolResultErrorFromErr("failed to create comment", err), nil, nil
+				}
+				defer func() { _ = resp.Body.Close() }()
+
+				if resp.StatusCode != http.StatusCreated {
+					bodyBytes, err := io.ReadAll(resp.Body)
+					if err != nil {
+						return utils.NewToolResultErrorFromErr("failed to read response body", err), nil, nil
+					}
+					return ghErrors.NewGitHubAPIStatusErrorResponse(ctx, "failed to create comment", resp, bodyBytes), nil, nil
+				}
+
+				commentResponse = &MinimalResponse{
+					ID:  fmt.Sprintf("%d", createdComment.GetID()),
+					URL: createdComment.GetHTMLURL(),
+				}
 			}
-			defer func() { _ = resp.Body.Close() }()
 
-			if resp.StatusCode != http.StatusCreated {
-				body, err := io.ReadAll(resp.Body)
+			var reactionResponse *MinimalResponse
+			if hasReaction {
+				reaction, resp, err := client.Reactions.CreateIssueReaction(ctx, owner, repo, issueNumber, reactionContent)
 				if err != nil {
-					return utils.NewToolResultErrorFromErr("failed to read response body", err), nil, nil
+					return ghErrors.NewGitHubAPIErrorResponse(ctx, "failed to add reaction to issue", resp, err), nil, nil
+				}
+				defer func() { _ = resp.Body.Close() }()
+
+				reactionResponse = &MinimalResponse{
+					ID:  fmt.Sprintf("%d", reaction.GetID()),
+					URL: fmt.Sprintf("%srepos/%s/%s/issues/%d/reactions/%d", client.BaseURL(), owner, repo, issueNumber, reaction.GetID()),
 				}
-				return ghErrors.NewGitHubAPIStatusErrorResponse(ctx, "failed to create comment", resp, body), nil, nil
 			}
 
-			minimalResponse := MinimalResponse{
-				ID:  fmt.Sprintf("%d", createdComment.GetID()),
-				URL: createdComment.GetHTMLURL(),
+			var result any
+			switch {
+			case hasBody && hasReaction:
+				result = map[string]MinimalResponse{
+					"comment":  *commentResponse,
+					"reaction": *reactionResponse,
+				}
+			case hasReaction:
+				result = reactionResponse
+			default:
+				result = commentResponse
 			}
 
-			r, err := json.Marshal(minimalResponse)
+			r, err := json.Marshal(result)
 			if err != nil {
 				return utils.NewToolResultErrorFromErr("failed to marshal response", err), nil, nil
 			}

pkg/github/issues_granular.go

@@ -1277,6 +1277,7 @@ func AddIssueReaction(t translations.TranslationHelperFunc) inventory.ServerTool
 			return utils.NewToolResultText(string(r)), nil, nil
 		},
 	)
+	st.FeatureFlagEnable = FeatureFlagIssuesGranular
 	return st
 }
 
@@ -1358,5 +1359,6 @@ func AddIssueCommentReaction(t translations.TranslationHelperFunc) inventory.Ser
 			return utils.NewToolResultText(string(r)), nil, nil
 		},
 	)
+	st.FeatureFlagEnable = FeatureFlagIssuesGranular
 	return st
 }