Add tools for one-off PR comments and replying to PR review comments

README.md

@@ -288,6 +288,29 @@ export GITHUB_MCP_TOOL_ADD_ISSUE_COMMENT_DESCRIPTION="an alternative description
   - `draft`: Create as draft PR (boolean, optional)
   - `maintainer_can_modify`: Allow maintainer edits (boolean, optional)
 
+- **add_pull_request_review_comment** - Add a review comment to a pull request
+
+  - `owner`: Repository owner (string, required)
+  - `repo`: Repository name (string, required)
+  - `pull_number`: Pull request number (number, required)
+  - `body`: The text of the review comment (string, required)
+  - `commit_id`: The SHA of the commit to comment on (string, required)
+  - `path`: The relative path to the file that necessitates a comment (string, required)
+  - `line`: The line of the blob in the pull request diff that the comment applies to (number, optional)
+  - `side`: The side of the diff to comment on (LEFT or RIGHT) (string, optional)
+  - `start_line`: For multi-line comments, the first line of the range (number, optional)
+  - `start_side`: For multi-line comments, the starting side of the diff (LEFT or RIGHT) (string, optional)
+  - `subject_type`: The level at which the comment is targeted (line or file) (string, optional)
+  - `in_reply_to`: The ID of the review comment to reply to (number, optional)
+
+- **reply_to_pull_request_review_comment** - Reply to an existing review comment on a pull request
+
+  - `owner`: Repository owner (string, required)
+  - `repo`: Repository name (string, required)
+  - `pull_number`: Pull request number (number, required)
+  - `comment_id`: The unique identifier of the comment to reply to (number, required)
+  - `body`: The text of the reply comment (string, required)
+
 - **update_pull_request** - Update an existing pull request in a GitHub repository
 
   - `owner`: Repository owner (string, required)

pkg/github/pullrequests.go

@@ -644,6 +644,236 @@ func GetPullRequestComments(getClient GetClientFn, t translations.TranslationHel
 		}
 }
 
+// AddPullRequestReviewComment creates a tool to add a review comment to a pull request.
+func AddPullRequestReviewComment(getClient GetClientFn, t translations.TranslationHelperFunc) (tool mcp.Tool, handler server.ToolHandlerFunc) {
+	return mcp.NewTool("add_pull_request_review_comment",
+			mcp.WithDescription(t("TOOL_ADD_PULL_REQUEST_COMMENT_DESCRIPTION", "Add a review comment to a pull request")),
+			mcp.WithString("owner",
+				mcp.Required(),
+				mcp.Description("Repository owner"),
+			),
+			mcp.WithString("repo",
+				mcp.Required(),
+				mcp.Description("Repository name"),
+			),
+			mcp.WithNumber("pull_number",
+				mcp.Required(),
+				mcp.Description("Pull request number"),
+			),
+			mcp.WithString("body",
+				mcp.Required(),
+				mcp.Description("The text of the review comment"),
+			),
+			mcp.WithString("commit_id",
+				mcp.Required(),
+				mcp.Description("The SHA of the commit to comment on"),
+			),
+			mcp.WithString("path",
+				mcp.Required(),
+				mcp.Description("The relative path to the file that necessitates a comment"),
+			),
+			mcp.WithString("subject_type",
+				mcp.Description("The level at which the comment is targeted, 'line' or 'file'"),
+				mcp.Enum("line", "file"),
+			),
+			mcp.WithNumber("line",
+				mcp.Description("The line of the blob in the pull request diff that the comment applies to. For multi-line comments, the last line of the range"),
+			),
+			mcp.WithString("side",
+				mcp.Description("The side of the diff to comment on. Can be LEFT or RIGHT"),
+				mcp.Enum("LEFT", "RIGHT"),
+			),
+			mcp.WithNumber("start_line",
+				mcp.Description("For multi-line comments, the first line of the range that the comment applies to"),
+			),
+			mcp.WithString("start_side",
+				mcp.Description("For multi-line comments, the starting side of the diff that the comment applies to. Can be LEFT or RIGHT"),
+				mcp.Enum("LEFT", "RIGHT"),
+			),
+			mcp.WithNumber("in_reply_to",
+				mcp.Description("The ID of the review comment to reply to. When specified, all parameters other than body are ignored"),
+			),
+		),
+		func(ctx context.Context, request mcp.CallToolRequest) (*mcp.CallToolResult, error) {
+			owner, err := requiredParam[string](request, "owner")
+			if err != nil {
+				return mcp.NewToolResultError(err.Error()), nil
+			}
+			repo, err := requiredParam[string](request, "repo")
+			if err != nil {
+				return mcp.NewToolResultError(err.Error()), nil
+			}
+			pullNumber, err := RequiredInt(request, "pull_number")
+			if err != nil {
+				return mcp.NewToolResultError(err.Error()), nil
+			}
+			body, err := requiredParam[string](request, "body")
+			if err != nil {
+				return mcp.NewToolResultError(err.Error()), nil
+			}
+			commitID, err := requiredParam[string](request, "commit_id")
+			if err != nil {
+				return mcp.NewToolResultError(err.Error()), nil
+			}
+			path, err := requiredParam[string](request, "path")
+			if err != nil {
+				return mcp.NewToolResultError(err.Error()), nil
+			}
+
+			comment := &github.PullRequestComment{
+				Body:     github.Ptr(body),
+				CommitID: github.Ptr(commitID),
+				Path:     github.Ptr(path),
+			}
+
+			// Check for in_reply_to parameter which takes precedence
+			if replyToFloat, ok := request.Params.Arguments["in_reply_to"].(float64); ok {
+				comment.InReplyTo = github.Ptr(int64(replyToFloat))
+			} else {
+				// Handle subject_type parameter
+				subjectType, err := OptionalParam[string](request, "subject_type")
+				if err != nil {
+					return mcp.NewToolResultError(err.Error()), nil
+				}
+				if subjectType != "file" {
+					// Handle line or position-based comments
+					// No action needed if subjectType is "file"
+					line, lineExists := request.Params.Arguments["line"].(float64)
+					startLine, startLineExists := request.Params.Arguments["start_line"].(float64)
+					side, sideExists := request.Params.Arguments["side"].(string)
+					startSide, startSideExists := request.Params.Arguments["start_side"].(string)
+
+					if subjectType != "file" && !lineExists {
+						return mcp.NewToolResultError("line parameter is required unless using subject_type:file or in_reply_to"), nil
+					}
+
+					if lineExists {
+						comment.Line = github.Ptr(int(line))
+					}
+					if sideExists {
+						comment.Side = github.Ptr(side)
+					}
+					if startLineExists {
+						comment.StartLine = github.Ptr(int(startLine))
+					}
+					if startSideExists {
+						comment.StartSide = github.Ptr(startSide)
+					}
+
+					// Validate multi-line comment parameters
+					if startLineExists && !lineExists {
+						return mcp.NewToolResultError("if start_line is provided, line must also be provided"), nil
+					}
+					if startSideExists && !sideExists {
+						return mcp.NewToolResultError("if start_side is provided, side must also be provided"), nil
+					}
+				}
+			}
+
+			client, err := getClient(ctx)
+			if err != nil {
+				return nil, fmt.Errorf("failed to get GitHub client: %w", err)
+			}
+
+			createdComment, resp, err := client.PullRequests.CreateComment(ctx, owner, repo, pullNumber, comment)
+			if err != nil {
+				return nil, fmt.Errorf("failed to create pull request comment: %w", err)
+			}
+			defer func() { _ = resp.Body.Close() }()
+
+			if resp.StatusCode != http.StatusCreated {
+				body, err := io.ReadAll(resp.Body)
+				if err != nil {
+					return nil, fmt.Errorf("failed to read response body: %w", err)
+				}
+				return mcp.NewToolResultError(fmt.Sprintf("failed to create pull request comment: %s", string(body))), nil
+			}
+
+			r, err := json.Marshal(createdComment)
+			if err != nil {
+				return nil, fmt.Errorf("failed to marshal response: %w", err)
+			}
+
+			return mcp.NewToolResultText(string(r)), nil
+		}
+}
+
+// ReplyToPullRequestReviewComment creates a tool to reply to an existing review comment on a pull request.
+func ReplyToPullRequestReviewComment(getClient GetClientFn, t translations.TranslationHelperFunc) (tool mcp.Tool,
+	handler server.ToolHandlerFunc) {
+	return mcp.NewTool("reply_to_pull_request_review_comment",
+			mcp.WithDescription(t("TOOL_REPLY_TO_PULL_REQUEST_REVIEW_COMMENT_DESCRIPTION", "Reply to an existing review comment on a pull request")),
+			mcp.WithString("owner",
+				mcp.Required(),
+				mcp.Description("Repository owner"),
+			),
+			mcp.WithString("repo",
+				mcp.Required(),
+				mcp.Description("Repository name"),
+			),
+			mcp.WithNumber("pull_number",
+				mcp.Required(),
+				mcp.Description("Pull request number"),
+			),
+			mcp.WithNumber("comment_id",
+				mcp.Required(),
+				mcp.Description("The unique identifier of the comment to reply to"),
+			),
+			mcp.WithString("body",
+				mcp.Required(),
+				mcp.Description("The text of the reply comment"),
+			),
+		),
+		func(ctx context.Context, request mcp.CallToolRequest) (*mcp.CallToolResult, error) {
+			owner, err := requiredParam[string](request, "owner")
+			if err != nil {
+				return mcp.NewToolResultError(err.Error()), nil
+			}
+			repo, err := requiredParam[string](request, "repo")
+			if err != nil {
+				return mcp.NewToolResultError(err.Error()), nil
+			}
+			pullNumber, err := RequiredInt(request, "pull_number")
+			if err != nil {
+				return mcp.NewToolResultError(err.Error()), nil
+			}
+			commentID, err := RequiredInt(request, "comment_id")
+			if err != nil {
+				return mcp.NewToolResultError(err.Error()), nil
+			}
+			body, err := requiredParam[string](request, "body")
+			if err != nil {
+				return mcp.NewToolResultError(err.Error()), nil
+			}
+
+			client, err := getClient(ctx)
+			if err != nil {
+				return nil, fmt.Errorf("failed to get GitHub client: %w", err)
+			}
+
+			createdReply, resp, err := client.PullRequests.CreateCommentInReplyTo(ctx, owner, repo, pullNumber, body, int64(commentID))
+			if err != nil {
+				return nil, fmt.Errorf("failed to reply to pull request comment: %w", err)
+			}
+			defer func() { _ = resp.Body.Close() }()
+
+			if resp.StatusCode != http.StatusCreated {
+				body, err := io.ReadAll(resp.Body)
+				if err != nil {
+					return nil, fmt.Errorf("failed to read response body: %w", err)
+				}
+				return mcp.NewToolResultError(fmt.Sprintf("failed to reply to pull request comment: %s", string(body))), nil
+			}
+
+			r, err := json.Marshal(createdReply)
+			if err != nil {
+				return nil, fmt.Errorf("failed to marshal response: %w", err)
+			}
+
+			return mcp.NewToolResultText(string(r)), nil
+		}
+}
+
 // GetPullRequestReviews creates a tool to get the reviews on a pull request.
 func GetPullRequestReviews(getClient GetClientFn, t translations.TranslationHelperFunc) (tool mcp.Tool, handler server.ToolHandlerFunc) {
 	return mcp.NewTool("get_pull_request_reviews",