feat: add support for replying to existing epic comments

The epics-create-comment tool now accepts an optional replyToCommentId
parameter to create nested comment replies, mirroring the existing
stories-create-comment pattern. Uses the dedicated
createEpicCommentComment API endpoint for threaded replies.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: web-flow

src/client/shortcut.ts

@@ -3,6 +3,7 @@ import { readFileSync } from "node:fs";
 import { basename } from "node:path";
 import type {
 	ShortcutClient as BaseClient,
+	CreateCommentComment,
 	CreateDoc,
 	CreateEpic,
 	CreateEpicComment,
@@ -460,6 +461,23 @@ export class ShortcutClientWrapper {
 		return epicComment;
 	}
 
+	async createEpicCommentComment(
+		epicPublicId: number,
+		commentPublicId: number,
+		params: CreateCommentComment,
+	): Promise<ThreadedComment> {
+		const response = await this.client.createEpicCommentComment(
+			epicPublicId,
+			commentPublicId,
+			params,
+		);
+		const epicComment = response?.data ?? null;
+
+		if (!epicComment) throw new Error(`Failed to create the comment reply: ${response.status}`);
+
+		return epicComment;
+	}
+
 	async createEpic(params: CreateEpic): Promise<Epic> {
 		const response = await this.client.createEpic(params);
 		const epic = response?.data ?? null;

src/tools/epics.test.ts

@@ -488,6 +488,38 @@ describe("EpicTools", () => {
 				}),
 			).toThrow("Epic comment text is required");
 		});
+
+		test("should create a reply to an existing comment", async () => {
+			const createEpicCommentCommentMock = mock(
+				async (_epicId: number, _commentId: number, _params: { text: string }) => ({
+					id: 200,
+					text: "Reply comment",
+					app_url: "https://app.shortcut.com/test/epic/1/comments/200",
+				}),
+			);
+			const mockClient = createMockClient({
+				getEpic: getEpicMock,
+				createEpicComment: createEpicCommentMock,
+				createEpicCommentComment: createEpicCommentCommentMock,
+			});
+			const epicTools = new EpicTools(mockClient);
+			const result = await epicTools.createEpicComment({
+				epicPublicId: 1,
+				replyToCommentId: 100,
+				text: "Reply comment",
+			});
+
+			expect(getTextContent(result)).toBe(
+				"Created comment on epic 1. Comment URL: https://app.shortcut.com/test/epic/1/comments/200.",
+			);
+			expect(createEpicCommentMock).not.toHaveBeenCalled();
+			expect(createEpicCommentCommentMock).toHaveBeenCalledTimes(1);
+			expect(createEpicCommentCommentMock.mock.calls?.[0]?.[0]).toBe(1);
+			expect(createEpicCommentCommentMock.mock.calls?.[0]?.[1]).toBe(100);
+			expect(createEpicCommentCommentMock.mock.calls?.[0]?.[2]).toMatchObject({
+				text: "Reply comment",
+			});
+		});
 	});
 
 	describe("deleteEpic method", () => {

src/tools/epics.ts

@@ -98,6 +98,7 @@ export class EpicTools extends BaseTools {
 			"Add a comment to an epic.",
 			{
 				epicPublicId: z.number().positive().describe("Epic ID"),
+				replyToCommentId: z.number().positive().optional().describe("Comment ID to reply to"),
 				text: z.string().min(1).describe("Comment text"),
 			},
 			async (params) => await tools.createEpicComment(params),
@@ -208,9 +209,11 @@ export class EpicTools extends BaseTools {
 
 	async createEpicComment({
 		epicPublicId,
+		replyToCommentId,
 		text,
 	}: {
 		epicPublicId: number;
+		replyToCommentId?: number;
 		text: string;
 	}): Promise<CallToolResult> {
 		if (!epicPublicId) throw new Error("Epic public ID is required");
@@ -220,9 +223,13 @@ export class EpicTools extends BaseTools {
 		if (!epic)
 			throw new Error(`Failed to retrieve Shortcut epic with public ID: ${epicPublicId}`);
 
-		const epicComment = await this.client.createEpicComment(epicPublicId, {
-			text,
-		});
+		const epicComment = replyToCommentId
+			? await this.client.createEpicCommentComment(epicPublicId, replyToCommentId, {
+					text,
+				})
+			: await this.client.createEpicComment(epicPublicId, {
+					text,
+				});
 
 		return this.toResult(
 			`Created comment on epic ${epicPublicId}. Comment URL: ${epicComment.app_url}.`,