Sendbl

Create sendbl file-exchange links — request files from someone, send a file, check link status, list files in a link, or delete a link. Use when the user wan...

Create and manage sendbl file-exchange links from the assistant. sendbl is a file-transfer API for LLM agents: links to collect files from someone, or to send a file to someone, with quotas and expiry.

Setup (one-time)

1. Sign in at https://sendbl.com/account with Google.

2. Open https://sendbl.com/account/tokens and create a personal access token. Treat this token as a password: store it only in your environment, revoke it from the same page if it is ever exposed, and rotate it periodically.

3. Set the env var:

   export SENDBL_API_KEY="sk_pat_..."
   

The skill will not work without SENDBL_API_KEY.

API base URL

All endpoints below are relative to:

https://api.sendbl.com/v1

All API key calls send the key as the x-api-key header.

Capabilities

1. Request files from someone

When the user wants someone else to upload files to them.

curl -sS -X POST "https://api.sendbl.com/v1/requestFiles" \
  -H "x-api-key: $SENDBL_API_KEY" \
  -H "content-type: application/json" \
  -d '{
    "expires_in_hours": 72,
    "max_files": 10,
    "purpose": "<short reason>",
    "message": "<optional note shown to uploader>"
  }'

Returns upload_url (share with the counterparty), download_url (for retrieval), owner_token (keep — required for delete and list-files), and upload_link_id.

After calling, tell the user to save owner_token and upload_link_id — they cannot be recovered later.

2. Send a file to someone

When the user wants to share a single file. This is the convenience wrapper.

curl -sS -X POST "https://api.sendbl.com/v1/sendFile" \
  -H "x-api-key: $SENDBL_API_KEY" \
  -H "content-type: application/json" \
  -d '{
    "recipient_name": "<name or email>",
    "filename": "<file.ext>",
    "purpose": "<short reason>",
    "message": "<optional note>"
  }'

Returns presigned_upload_url (PUT the actual bytes there), download_url (share with recipient — null until upload completes), owner_token, and file_id.

The skill itself does not upload bytes. Instruct the user to PUT the file:

curl -X PUT --data-binary @<local-file> "<presigned_upload_url>"

3. Check link status (no auth)

curl -sS "https://api.sendbl.com/v1/uploadLinkStatus?upload_link_id=<id>"

Returns status (open / closed / expired), expires_at, file_count. Use when the user pastes a link and wants to know if it's still valid.

4. List files in a link

Requires the owner_token from step 1 (or 2).

curl -sS "https://api.sendbl.com/v1/uploadedFiles?token=<owner_token>&limit=50"

Returns the array of files with file_id and filename. To get a download URL for one of them:

curl -sS "https://api.sendbl.com/v1/fileDownloadLink?token=<owner_token>&file_id=<file_id>"

5. Delete a link

Requires the owner_token. Removes the link and all uploaded files.

curl -sS -X DELETE "https://api.sendbl.com/v1/uploadLink?token=<owner_token>"

Confirm with the user before calling — this is irreversible.

Errors

• 401 unauthorized — missing or invalid x-api-key / owner_token. If the skill worked previously and now returns 401, the token has likely been revoked — instruct the user to issue a new one at https://sendbl.com/account/tokens.
• 403 forbidden — token role mismatch (e.g., uploader token used for owner action).
• 429 quota_exceeded — API key has hit the monthly link limit. Surface this verbatim; do not retry.
• 404 link_not_found — link expired or was deleted.

Conventions

• Never POST file bytes to the sendbl API. Bytes always go to the presigned S3 URL via PUT.
• Always remind the user to save owner_token and upload_link_id after creating a link — they're not retrievable later.
• Treat download_url and upload_url as different audiences: upload URL goes to the sender, download URL goes to the recipient.
• Default expires_in_hours to 72 unless the user specifies otherwise.