MCP tool returns base64 encoded binary of an image which cause bedrock threw context window overflow error

[dastagirS]

ive followed the instruction of setting up mcp tools. One of my mcp tool returns an base64 encoded image binary. ive setup a formatter tool which converts base64 to strands contentblock for image name base64_image_reader . but the agent fail right after it recieves the output from the mcp tool. saying

strands.models.bedrock - WARNING - bedrock threw context window overflow error

the mcp tool return in this format:

            "status": "success",
            "attachment": {
                "type":"base64",
                "data":data,
                "mimeType":mime_type,
              }

edit:

ive even tried returning in

   "status": "success",
           "image": {
               "source": {"bytes": base64.b64decode(data)},
               "format":mime_type,
             }