Media

Bots can send photos and documents with optional captions.

Buko does not accept remote media URLs. Your agent must upload bytes using multipart/form-data. This avoids SSRF risk and keeps media retention under Buko's normal chat storage policy.

Limits

Method	Field	Max size
`sendPhoto`	`photo`	20 MB
`sendDocument`	`document`	50 MB

Captions can be up to 5000 characters.

`sendPhoto`

POST https://ims.buko.app/bot/sendPhoto

Multipart fields:

Field	Required	Description
`chat_id`	yes	Target Buko `space_id`.
`photo`	yes	Image file. Must have an image MIME type.
`caption`	no	Optional caption.
`reply_to_message_id`	no	Message `seq` in the same chat.

Example:

curl -sS https://ims.buko.app/bot/sendPhoto \
  -X POST \
  -H "Authorization: Bot $BUKO_BOT_TOKEN" \
  -F "chat_id=spc_abc123" \
  -F "caption=Here is the chart." \
  -F "photo=@./chart.png;type=image/png"

Response:

{
  "ok": true,
  "result": {
    "message_id": "44",
    "chat": { "id": "spc_abc123", "type": "private" },
    "date": 1783000000,
    "caption": "Here is the chart.",
    "photo": [
      {
        "file_id": "media/spc_abc123/...",
        "mime_type": "image/png",
        "file_size": 12345
      }
    ]
  }
}

`sendDocument`

POST https://ims.buko.app/bot/sendDocument

Multipart fields:

Field	Required	Description
`chat_id`	yes	Target Buko `space_id`.
`document`	yes	File bytes.
`caption`	no	Optional caption.
`reply_to_message_id`	no	Message `seq` in the same chat.

Example:

curl -sS https://ims.buko.app/bot/sendDocument \
  -X POST \
  -H "Authorization: Bot $BUKO_BOT_TOKEN" \
  -F "chat_id=spc_abc123" \
  -F "caption=Monthly report" \
  -F "document=@./report.pdf;type=application/pdf"

Storage behavior

Bot media is stored using the same Buko media pipeline as user media:

the agent uploads bytes
Buko commits the media into the target chat
clients receive a normal media message
media follows the chat retention policy

The client never needs to know about temporary upload keys.