From 4b6c51f32e794b169606327e76c13694bc699b5e Mon Sep 17 00:00:00 2001
From: Yufeng He <40085740+he-yufeng@users.noreply.github.com>
Date: Sat, 30 May 2026 06:44:23 +0800
Subject: [PATCH] fix: normalize media format mappings

---
 strands-py/src/strands/models/anthropic.py    | 13 ++++++++++-
 strands-py/src/strands/models/bedrock.py      |  6 ++++-
 strands-py/src/strands/types/media.py         |  2 +-
 .../tests/strands/models/test_anthropic.py    | 22 +++++++++++++++++++
 .../tests/strands/models/test_bedrock.py      | 21 ++++++++++++++++++
 5 files changed, 61 insertions(+), 3 deletions(-)

diff --git a/strands-py/src/strands/models/anthropic.py b/strands-py/src/strands/models/anthropic.py
index 812171a0cf..d26f396cad 100644
--- a/strands-py/src/strands/models/anthropic.py
+++ b/strands-py/src/strands/models/anthropic.py
@@ -28,6 +28,14 @@
 
 T = TypeVar("T", bound=BaseModel)
 
+_IMAGE_MEDIA_TYPES = {
+    "gif": "image/gif",
+    "jpeg": "image/jpeg",
+    "jpg": "image/jpeg",
+    "png": "image/png",
+    "webp": "image/webp",
+}
+
 
 class AnthropicModel(Model):
     """Anthropic model provider implementation."""
@@ -131,10 +139,13 @@ def _format_request_message_content(self, content: ContentBlock) -> dict[str, An
             }
 
         if "image" in content:
+            image_format = content["image"]["format"]
             return {
                 "source": {
                     "data": base64.b64encode(content["image"]["source"]["bytes"]).decode("utf-8"),
-                    "media_type": mimetypes.types_map.get(f".{content['image']['format']}", "application/octet-stream"),
+                    "media_type": _IMAGE_MEDIA_TYPES.get(
+                        image_format.lower(), mimetypes.types_map.get(f".{image_format}", "application/octet-stream")
+                    ),
                     "type": "base64",
                 },
                 "type": "image",
diff --git a/strands-py/src/strands/models/bedrock.py b/strands-py/src/strands/models/bedrock.py
index bc9ce6c0f9..4c0e5cc61c 100644
--- a/strands-py/src/strands/models/bedrock.py
+++ b/strands-py/src/strands/models/bedrock.py
@@ -37,6 +37,7 @@
 from .model import BaseModelConfig, CacheConfig, CacheToolsConfig, Model
 
 logger = logging.getLogger(__name__)
+_VIDEO_FORMAT_ALIASES = {"3gp": "three_gp"}
 
 # See: `BedrockModel._get_default_model_with_warning` for why we need both
 DEFAULT_BEDROCK_MODEL_ID = "global.anthropic.claude-sonnet-4-6"
@@ -702,7 +703,10 @@ def _format_request_message_content(self, content: ContentBlock) -> dict[str, An
                     return None
             elif "bytes" in source:
                 formatted_video_source = {"bytes": source["bytes"]}
-            result = {"format": video["format"], "source": formatted_video_source}
+            result = {
+                "format": _VIDEO_FORMAT_ALIASES.get(video["format"], video["format"]),
+                "source": formatted_video_source,
+            }
             return {"video": result}
 
         # https://docs.aws.amazon.com/bedrock/latest/APIReference/API_runtime_CitationsContentBlock.html
diff --git a/strands-py/src/strands/types/media.py b/strands-py/src/strands/types/media.py
index b1240dffb1..00daf6dad7 100644
--- a/strands-py/src/strands/types/media.py
+++ b/strands-py/src/strands/types/media.py
@@ -107,7 +107,7 @@ class ImageContent(TypedDict):
     source: ImageSource
 
 
-VideoFormat = Literal["flv", "mkv", "mov", "mpeg", "mpg", "mp4", "three_gp", "webm", "wmv"]
+VideoFormat = Literal["flv", "mkv", "mov", "mpeg", "mpg", "mp4", "3gp", "three_gp", "webm", "wmv"]
 """Supported video formats."""
 
 
diff --git a/strands-py/tests/strands/models/test_anthropic.py b/strands-py/tests/strands/models/test_anthropic.py
index 0ebdb161c6..819343b61a 100644
--- a/strands-py/tests/strands/models/test_anthropic.py
+++ b/strands-py/tests/strands/models/test_anthropic.py
@@ -254,6 +254,28 @@ def test_format_request_with_image(model, model_id, max_tokens):
     assert tru_request == exp_request
 
 
+def test_format_request_with_webp_image_uses_explicit_media_type(model, monkeypatch):
+    monkeypatch.delitem(strands.models.anthropic.mimetypes.types_map, ".webp", raising=False)
+
+    messages = [
+        {
+            "role": "user",
+            "content": [
+                {
+                    "image": {
+                        "format": "webp",
+                        "source": {"bytes": b"webpimage"},
+                    },
+                },
+            ],
+        },
+    ]
+
+    tru_request = model.format_request(messages)
+
+    assert tru_request["messages"][0]["content"][0]["source"]["media_type"] == "image/webp"
+
+
 def test_format_request_with_reasoning(model, model_id, max_tokens):
     messages = [
         {
diff --git a/strands-py/tests/strands/models/test_bedrock.py b/strands-py/tests/strands/models/test_bedrock.py
index 179c3dce48..6b52436ba2 100644
--- a/strands-py/tests/strands/models/test_bedrock.py
+++ b/strands-py/tests/strands/models/test_bedrock.py
@@ -2254,6 +2254,27 @@ def test_format_request_video_s3_location(model, model_id):
     assert video_source == {"s3Location": {"uri": "s3://my-bucket/video.mp4"}}
 
 
+def test_format_request_video_3gp_maps_bedrock_enum(model, model_id):
+    messages = [
+        {
+            "role": "user",
+            "content": [
+                {
+                    "video": {
+                        "format": "3gp",
+                        "source": {"bytes": b"video_data"},
+                    }
+                },
+            ],
+        }
+    ]
+
+    formatted_request = model._format_request(messages)
+    video_block = formatted_request["messages"][0]["content"][0]["video"]
+
+    assert video_block == {"format": "three_gp", "source": {"bytes": b"video_data"}}
+
+
 def test_format_request_filters_document_content_blocks(model, model_id):
     """Test that format_request filters extra fields from document content blocks."""
     messages = [