Function sendSlackMessage

apps/sim/app/api/tools/slack/utils.ts:249–343

(
  params: SlackMessageParams,
  requestId: string,
  logger: Logger
)

 * Supports both channel messages and direct messages via userId
 */
export async function sendSlackMessage(
  params: SlackMessageParams,
  requestId: string,
  logger: Logger
): Promise<{
  success: boolean
  output?: {
    message: any
    ts: string
    channel: string
    fileCount?: number
    files?: ToolFileData[]
  }
  error?: string
}> {
  const { accessToken, text, threadTs, blocks, files, ownerUserId } = params
  let { channel } = params

  if (!channel && params.userId) {
    logger.info(`[${requestId}] Opening DM channel for user: ${params.userId}`)
    channel = await openDMChannel(accessToken, params.userId, requestId, logger)
  }

  if (!channel) {
    return { success: false, error: 'Either channel or userId is required' }
  }

  // No files - simple message
  if (!files || files.length === 0) {
    logger.info(`[${requestId}] No files, using chat.postMessage`)

    const data = await postSlackMessage(accessToken, channel, text, threadTs, blocks)

    if (!data.ok) {
      logger.error(`[${requestId}] Slack API error:`, data.error)
      return { success: false, error: data.error || 'Failed to send message' }
    }

    logger.info(`[${requestId}] Message sent successfully`)
    return { success: true, output: formatMessageSuccessResponse(data, text) }
  }

  // Process files
  logger.info(`[${requestId}] Processing ${files.length} file(s)`)
  const { fileIds, files: uploadedFiles } = await uploadFilesToSlack(
    files,
    accessToken,
    requestId,
    logger,
    ownerUserId
  )

  // No valid files uploaded - send text-only
  if (fileIds.length === 0) {
    logger.warn(`[${requestId}] No valid files to upload, sending text-only message`)

    const data = await postSlackMessage(accessToken, channel, text, threadTs, blocks)