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POST
Complete an attachment upload
Write access: a member/administrator with a write-enabled credential, or an authorized signed-in user. Verify the uploaded image/PDF and attach it to the task. Invalid bytes, size or type are rejected; reuse the Idempotency-Key header on retries. Checks byte length, detected MIME/signature and optional SHA-256. Mill copies verified bytes to a final object. An expired upload returns 410 UPLOAD_EXPIRED; start a new upload. MCP clients can use complete_attachment for this operation. Request conventions · API keys · MCP connections

Authorizations

Authorization
string
header
required

Personal or team Mill REST API key

Headers

Origin
string<uri>

The exact configured Mill UI origin. Required for browser mutations carrying session cookies.

Idempotency-Key
string

Reuse the same key and exact request bytes for retries of one logical mutation; different content conflicts.

Required string length: 8 - 128
Pattern: ^[A-Za-z0-9._:-]+$

Path Parameters

taskId
string<uuid>
required

The taskId from the corresponding list, record or authorization response.

attachmentId
string<uuid>
required

The attachmentId from the corresponding list, record or authorization response.

Response

Successful response. Examples are illustrative; field values vary by record.

Illustrative response shape. Fields can be absent in alternate successful flows; see the operation description and example.

attachment
object