이미지와 바이너리 데이터 반환하기

Some tools produce pictures or files, not words. MCP can return binary content like images and other blobs, not just text.

MCP defines an image content type carrying the raw bytes plus a media type. Clients that support it can render the picture directly. 🖼️

Binary data is encoded as base64 text so it survives the JSON message. The client decodes it back into real bytes on arrival.

The Python SDK offers an Image helper so you do not hand-encode anything. You point it at bytes or a path and return it.

Always state the format, like png or jpeg, so the client knows how to decode and display the image correctly.

Read the file into bytes, then wrap it for return. The tool turns a saved chart into a viewable result for the model and user.

Beyond pictures, MCP supports generic blob content for other binary data, like a PDF or audio, with its own media type.

Not every client can show every type. A host that cannot render an image may fall back to a reference or a download link.

Base64 inflates data by about a third, and large blobs eat tokens and bandwidth. Keep returned media small when you can.

For very large or shared files, expose a resource by URI instead of inlining bytes in a tool result. The client fetches on demand.

You can pair an image with a short text caption in the same result, giving the model both a picture and words to reason about.

How does binary data ride inside an MCP message?

You can return images and binary blobs via base64 with a media type, set the format, mind size, and prefer resources for big files. ✅