vercel/ai · error · UnsupportedFunctionalityError

file parts with provider references

Error message

file parts with provider references

What it means

File parts whose data is a provider reference (a previously uploaded file referenced by provider-specific ID) have no representation in the Bedrock chat payload, so the converter throws UnsupportedFunctionalityError with 'file parts with provider references'.

Source

Thrown at packages/amazon-bedrock/src/convert-to-amazon-bedrock-chat-messages.ts:227

                        guardContent: {
                          text: {
                            text: part.text,
                            qualifiers: textOptions.guardContentQualifiers,
                          },
                        },
                      });
                    } else {
                      amazonBedrockContent.push({
                        text: part.text,
                      });
                    }
                    break;
                  }

                  case 'file': {
                    switch (part.data.type) {
                      case 'reference': {
                        throw new UnsupportedFunctionalityError({
                          functionality: 'file parts with provider references',
                        });
                      }
                      case 'url': {
                        if (part.data.url.protocol !== 's3:') {
                          throw new UnsupportedFunctionalityError({
                            functionality: 'File URL data',
                          });
                        }

                        const fullMediaType = resolveFullMediaType({ part });

                        switch (getTopLevelMediaType(fullMediaType)) {
                          case 'image': {
                            amazonBedrockContent.push({
                              image: {
                                format:
                                  getAmazonBedrockImageFormat(fullMediaType),

View on GitHub (pinned to 69428b1f8b)

Solutions

1. Send the file as raw binary data instead: use a Uint8Array/Buffer in the file part's data.
2. For S3-hosted files, use a URL part with an s3: protocol URL.
3. Convert provider references to actual bytes before calling the Bedrock model.

Example fix

// before
{ type: 'file', data: new Uint8Array(...), mediaType: 'application/pdf' } // ok
{ type: 'file', data: { type: 'reference', fileId: 'file-abc' } } // throws
// after
const bytes = await fetchStoredFileBytes('file-abc');
{ type: 'file', data: bytes, mediaType: 'application/pdf' }

function assertNoFileReferences(messages) {
  for (const m of messages) {
    const parts = Array.isArray(m.content) ? m.content : [];
    for (const p of parts) {
      if (p.type === 'file' && p.data?.type === 'reference') {
        throw new Error('Bedrock cannot consume file parts by reference; send raw bytes or an s3:// URL.');
      }
    }
  }
}

function isFileReference(part: any): part is { type: 'file'; data: { type: 'reference'; fileId: string } } {
  return part?.type === 'file' && part?.data?.type === 'reference';
}

try {
  await streamText({ model: bedrock(modelId), messages });
} catch (error) {
  if (UnsupportedFunctionalityError.isInstance(error) && error.functionality.includes('provider references')) {
    // resolve reference to bytes and rebuild the message
  } else {
    throw error;
  }
}

When it happens

Trigger: Sending a message containing a file part with `data: { type: 'reference' }` (e.g. a file stored/uploaded via another provider's file API) to a Bedrock model via generateText/streamText.

Common situations: Reusing prompts built for OpenAI file IDs; multi-provider apps sharing message arrays that contain references; tool results carrying provider file references.

Related errors

• File URL data
• AI_UnsupportedFunctionalityError
• Unsupported task type: ${taskType}
• URL-based images are not supported for Amazon Bedrock image
• AI_UnsupportedFunctionalityError

AI-assisted analysis of vercel/ai@69428b1f8b (2026-08-30). Data as JSON: /api/errors/4b49389cd60e4f62. Report an issue: GitHub.