Cannot pass compound messages (anthropic - caching/sub-documents)

[Madd0g]

Bug Description

Claude supports something like this:

    messages = [
      %{
        role: "user",
        content: [
          %{
            type: "document",
            source: %{type: "base64", media_type: "application/pdf", data: pdf_file_content},
            cache_control: %{type: "ephemeral"}
          },
          %{type: "text", text: prompt}
        ]
      }
    ]

It explodes trying to measure the message size. Also the IDE complains the message structure is incorrect.

Steps to Reproduce

1. Pass a pdf.

Also, I'm not sure the cache flag is supported.

Environment

• ExLLM Version - 0.8.1 (latest from hex)
• Erlang/OTP 27 [erts-15.2.5] [source] [64-bit] [smp:16:16] [ds:16:16:10] [async-threads:1]
• IEx 1.18.3 (compiled with Erlang/OTP 27)

Error Output

I changed code already to use another library, sorry.

Additional Context

Also, I just remembered that nothing worked until I copied a folder full of yml files with model specific configs into the ex_llm dependency folder.

I think that's another problem in 0.8.1, that the configs are missing entirely.