BoundaryML/baml · error

not yet implemented

Error message

not yet implemented

What it means

This panic comes from a Rust `todo!()` in media_to_content_block_json when converting a chat media part for AWS Bedrock modular (Converse) requests. When the media content is a local file reference (BamlMediaContent::File), the AWS path has no implementation, so it panics with "not yet implemented" instead of returning a graceful error. It is a library limitation, not a problem with your model config.

Source

Thrown at engine/baml-runtime/src/internal/llm_client/primitive/aws/aws_client.rs:82

    },
    json_body,
    tracingv2::storage::storage::BAML_TRACER,
    JsonBodyInput, RenderCurlSettings, RuntimeContext,
};

// Strip the MIME type prefix ("type/subtype" -> "subtype").
fn strip_mime_prefix(mime: &str) -> &str {
    mime.split_once('/').map(|(_, s)| s).unwrap_or(mime)
}

fn media_to_content_block_json(media: &BamlMedia) -> Result<serde_json::Value> {
    let content_block = {
        let mut obj = Map::new();
        if let Some(mime) = media.mime_type.as_deref() {
            obj.insert("format".into(), json!(strip_mime_prefix(mime)));
        }
        let source = match &media.content {
            BamlMediaContent::File(media_file) => todo!(),
            BamlMediaContent::Url(url) => {
                let parsed = Url::parse(&url.url).with_context(|| {
                    format!("Invalid S3 URI for AWS Bedrock video source: {url}")
                })?;

                if parsed.scheme() != "s3" {
                    anyhow::bail!("AWS Bedrock requires s3:// URIs, but got: {}", url.url);
                }

                // unimplemented!("make sure the test works")
                json!({
                    "s3Location": {
                        "uri": url.url,
                    }
                })
            }
            BamlMediaContent::Base64(base64) => json!({
                "bytes": base64.base64,

View on GitHub (pinned to bd85ce9dee)

Solutions

1. Pass the media as a base64 data URL (e.g. data:image/png;base64,...) or an https:// URL rather than a local file path.
2. Set resolve_media_urls / media resolution options so BAML inlines file media into base64 before reaching the AWS client.
3. If you need file media on Bedrock, file an issue with BAML to implement BamlMediaContent::File in aws_client.rs, or patch the match arm to base64-encode the file.

Example fix

// before
media b "baml://./video.mp4"
// after
media b "data:video/mp4;base64,AAAAIGZ0eXBpc29t..."

if media.content is a local file reference:
    # resolve to base64 before sending to aws-bedrock
    media = to_base64_data_url(media)

def is_bedrock_safe_media(media) -> bool:
    c = media['content']
    return isinstance(c, dict) and ('base64' in c or str(c.get('url','')).startswith(('s3://', 'data:')))

When it happens

Trigger: Calling chat/stream_chat on an aws-bedrock client whose rendered message contains a media part (image/pdf/video/audio) loaded from a local File (e.g. baml './file.png' or file:// content) instead of a URL or base64 payload.

Common situations: Developers testing Bedrock multimodal (e.g. Nova video) prompts with media referenced from local disk; CI environments where media was expected to be resolved to base64 but stayed as a file reference.

Related errors

• exprs that evaluate to lambda
• AWS Bedrock requires s3:// URIs, but got: {}
• AWS Bedrock only supports text system blocks, but got {other
• Invalid client property. Should have been a aws-bedrock prop
• AWS Bedrock modular streaming is not supported. Use non-stre

AI-assisted analysis of BoundaryML/baml@bd85ce9dee (2026-09-12). Data as JSON: /api/errors/6de86311d23b46ed. Report an issue: GitHub.