Function uploadBriefAttachment

src/tools/BriefTool/upload.ts:92–174

(
  fullPath: string,
  size: number,
  ctx: BriefUploadContext,
)

 * Every early-return is intentional graceful degradation.
 */
export async function uploadBriefAttachment(
  fullPath: string,
  size: number,
  ctx: BriefUploadContext,
): Promise<string | undefined> {
  // Positive pattern so bun:bundle eliminates the entire body from
  // non-BRIDGE_MODE builds (negative `if (!feature(...)) return` does not).
  if (feature('BRIDGE_MODE')) {
    if (!ctx.replBridgeEnabled) return undefined

    if (size > MAX_UPLOAD_BYTES) {
      debug(`skip ${fullPath}: ${size} bytes exceeds ${MAX_UPLOAD_BYTES} limit`)
      return undefined
    }

    const token = getBridgeAccessToken()
    if (!token) {
      debug('skip: no oauth token')
      return undefined
    }

    let content: Buffer
    try {
      content = await readFile(fullPath)
    } catch (e) {
      debug(`read failed for ${fullPath}: ${e}`)
      return undefined
    }

    const baseUrl = getBridgeBaseUrl()
    const url = `${baseUrl}/api/oauth/file_upload`
    const filename = basename(fullPath)
    const mimeType = guessMimeType(filename)
    const boundary = `----FormBoundary${randomUUID()}`

    // Manual multipart — same pattern as filesApi.ts. The oauth endpoint takes
    // a single "file" part (no "purpose" field like the public Files API).
    const body = Buffer.concat([
      Buffer.from(
        `--${boundary}\r\n` +
          `Content-Disposition: form-data; name="file"; filename="${filename}"\r\n` +
          `Content-Type: ${mimeType}\r\n\r\n`,
      ),
      content,
      Buffer.from(`\r\n--${boundary}--\r\n`),
    ])

    try {
      const response = await axios.post(url, body, {
        headers: {
          Authorization: `Bearer ${token}`,
          'Content-Type': `multipart/form-data; boundary=${boundary}`,
          'Content-Length': body.length.toString(),
        },
        timeout: UPLOAD_TIMEOUT_MS,
        signal: ctx.signal,
        validateStatus: () => true,
      })