slack_reply_to_thread

Post replies to specific message threads in Slack channels to maintain organized conversations and follow discussions.

Instructions

Reply to a specific message thread in Slack

Input Schema

TableJSON Schema

Name	Required	Description
`channel_id`	Yes	The ID of the channel containing the thread
`thread_ts`	Yes	The timestamp of the parent message in the format '1234567890.123456'. Timestamps in the format without the period can be converted by adding the period such that 6 numbers come after it.
`text`	Yes	The reply text

Implementation Reference

index.ts:277-282 (handler)

MCP tool handler: extracts parameters and calls slackClient.postReply, then returns formatted response.

async ({ channel_id, thread_ts, text }) => {
  const response = await slackClient.postReply(channel_id, thread_ts, text);
  return {
    content: [{ type: "text", text: JSON.stringify(response) }],
  };
}

index.ts:268-275 (schema)

Tool metadata including title, description, and Zod input schema for parameters.

{
  title: "Reply to Slack Thread",
  description: "Reply to a specific message thread in Slack",
  inputSchema: {
    channel_id: z.string().describe("The ID of the channel containing the thread"),
    thread_ts: z.string().describe("The timestamp of the parent message in the format '1234567890.123456'. Timestamps in the format without the period can be converted by adding the period such that 6 numbers come after it."),
    text: z.string().describe("The reply text"),
  },

index.ts:266-283 (registration)

Registration of the 'slack_reply_to_thread' tool on the MCP server, including schema and inline handler.

server.registerTool(
  "slack_reply_to_thread",
  {
    title: "Reply to Slack Thread",
    description: "Reply to a specific message thread in Slack",
    inputSchema: {
      channel_id: z.string().describe("The ID of the channel containing the thread"),
      thread_ts: z.string().describe("The timestamp of the parent message in the format '1234567890.123456'. Timestamps in the format without the period can be converted by adding the period such that 6 numbers come after it."),
      text: z.string().describe("The reply text"),
    },
  },
  async ({ channel_id, thread_ts, text }) => {
    const response = await slackClient.postReply(channel_id, thread_ts, text);
    return {
      content: [{ type: "text", text: JSON.stringify(response) }],
    };
  }
);

index.ts:124-140 (helper)

SlackClient.postReply method: core implementation that calls Slack's chat.postMessage API with thread_ts to reply in thread.

async postReply(
  channel_id: string,
  thread_ts: string,
  text: string,
): Promise<any> {
  const response = await fetch("https://slack.com/api/chat.postMessage", {
    method: "POST",
    headers: this.botHeaders,
    body: JSON.stringify({
      channel: channel_id,
      thread_ts: thread_ts,
      text: text,
    }),
  });

  return response.json();
}

Slack