feat(media): add S3 location support to image, document, and video content types

[github-actions]

Summary

Adds native S3 location support for media content types in Bedrock, allowing users to reference images, documents, and videos stored in S3 directly rather than requiring base64 encoding.

Why

Currently users must download media from S3 and base64-encode it before sending to Bedrock. This feature enables direct S3 references, reducing memory usage and simplifying workflows for S3-hosted content. This is particularly valuable for large media files where base64 encoding is impractical.

What Changed

Type System Updates

• Extended ImageSource, DocumentSource, and VideoSource in types/media.py to accept s3Location as an alternative to bytes
• Added S3Location TypedDict with required uri field and optional bucketOwner for cross-account access

Provider Behavior

• Bedrock: Passes S3 locations through unchanged to the API
• Non-Bedrock providers: Filter S3 sources with a warning since they don't support S3 references

Code Consolidation

• Centralized S3 source detection in _validation.has_s3_source() helper function
• Removed duplicate _has_s3_source() methods from individual model providers

Usage Example

from strands import Agent
from strands.models.bedrock import BedrockModel

agent = Agent(model=BedrockModel())

# Reference an S3-hosted document directly
response = agent(
    [
        {
            "role": "user",
            "content": [
                {"text": "Summarize this document:"},
                {
                    "document": {
                        "format": "pdf",
                        "name": "report.pdf",
                        "source": {
                            "s3Location": {
                                "uri": "s3://my-bucket/documents/report.pdf",
                                "bucketOwner": "123456789012"  # Optional
                            }
                        }
                    }
                }
            ]
        }
    ]
)

Testing

• Unit tests verify S3 location formatting in Bedrock requests
• Unit tests verify S3 source filtering with warnings in non-Bedrock providers
• Integration tests validate end-to-end S3 document processing

Resolves #10

[Unshure]

Can you turn this into a centralized helper method, and update the pr to use it

[github-actions]

+1. Consider adding this as a helper function in src/strands/types/media.py since it operates on the media content types defined there, or in a shared utilities module under src/strands/models/. That would keep the model implementations DRY and ensure consistent behavior across all providers.

[github-actions]

Done - centralized as _has_s3_source() in src/strands/models/_validation.py and all providers now use it.

[Unshure]

top-level imports

[Unshure]

top-level imports

[Unshure]

top-level imports

[Unshure]

/strands

[Unshure]

/strands review

[github-actions]

Review Summary

Assessment: Request Changes

Key Themes:

1. Type correctness - The S3Location TypedDict needs uri to be required per AWS Bedrock API docs
2. Code duplication - The _has_s3_source helper is duplicated across 8 model files; should be centralized
3. Test conventions - Imports should be at module level, not inside test functions (affects both test_anthropic.py and test_openai.py)
4. Test coverage - Integration test requested to validate end-to-end S3 functionality

The feature implementation looks solid - the Bedrock S3 handling is correct, and the warning/skip pattern for unsupported providers is a good approach. Once the above items are addressed, this PR will be ready to merge.

Nice work on the comprehensive coverage across all model providers! 🎉

[Unshure]

/strands

[Unshure]

/strands can you add unit tests to this pull request to cover the missing model providers? You should be able to add a simple test to most model providers that passes in an s3location content block, and asserts that a warning is thrown and the content is removed in the api call.