diff --git a/docs/input.md b/docs/input.md
index 0271e216af..71caaf4b5e 100644
--- a/docs/input.md
+++ b/docs/input.md
@@ -143,7 +143,7 @@ Support for file URLs varies depending on type and provider:
 
 | Model | Send URL directly | Download and send bytes | Unsupported |
 |-------|-------------------|-------------------------|-------------|
-| [`OpenAIChatModel`][pydantic_ai.models.openai.OpenAIChatModel] | `ImageUrl` | `AudioUrl`, `DocumentUrl` | `VideoUrl`. `DocumentUrl` [not supported with `AzureProvider`](models/openai.md#using-azure-with-the-responses-api) |
+| [`OpenAIChatModel`][pydantic_ai.models.openai.OpenAIChatModel] | `ImageUrl` | `AudioUrl`, `DocumentUrl` | `VideoUrl`. `DocumentUrl` [not supported with `AzureProvider`](models/openai.md#using-azure-with-the-responses-api) or [`AlibabaProvider`](models/openai.md#alibaba-cloud-model-studio-dashscope) |
 | [`OpenAIResponsesModel`][pydantic_ai.models.openai.OpenAIResponsesModel] | `ImageUrl`, `AudioUrl`, `DocumentUrl` | — | `VideoUrl` |
 | [`AnthropicModel`][pydantic_ai.models.anthropic.AnthropicModel] | `ImageUrl`, `DocumentUrl` (PDF) | `DocumentUrl` (`text/plain`) | `AudioUrl`, `VideoUrl` |
 | [`GoogleModel`][pydantic_ai.models.google.GoogleModel] (Google Cloud) | All URL types | — | — |
diff --git a/docs/models/openai.md b/docs/models/openai.md
index 6617f2c845..53f73350c9 100644
--- a/docs/models/openai.md
+++ b/docs/models/openai.md
@@ -467,6 +467,9 @@ agent = Agent(model)
 ...
 ```
 
+!!! note "Document input is not supported"
+    The DashScope compatible-mode Chat Completions API does not accept document content parts, so passing a [`DocumentUrl`][pydantic_ai.messages.DocumentUrl] or document [`BinaryContent`][pydantic_ai.messages.BinaryContent] to an [`OpenAIChatModel`][pydantic_ai.models.openai.OpenAIChatModel] backed by [`AlibabaProvider`][pydantic_ai.providers.alibaba.AlibabaProvider] raises a `UserError`.
+
 ### Ollama
 
 See [Ollama](ollama.md) for dedicated Ollama documentation, including structured output and Ollama Cloud limitations.
diff --git a/pydantic_ai_slim/pydantic_ai/providers/alibaba.py b/pydantic_ai_slim/pydantic_ai/providers/alibaba.py
index e02564c7f1..96a64b08a9 100644
--- a/pydantic_ai_slim/pydantic_ai/providers/alibaba.py
+++ b/pydantic_ai_slim/pydantic_ai/providers/alibaba.py
@@ -41,8 +41,13 @@ def client(self) -> AsyncOpenAI:
     def model_profile(model_name: str) -> ModelProfile | None:
         base_profile = qwen_model_profile(model_name)
 
-        # Wrap/merge into OpenAIModelProfile
-        openai_profile = OpenAIModelProfile(json_schema_transformer=OpenAIJsonSchemaTransformer).update(base_profile)
+        # Wrap/merge into OpenAIModelProfile.
+        # Alibaba's compatible-mode Chat Completions API rejects OpenAI `type:file` content parts,
+        # so document input must fail client-side with a clear UserError.
+        openai_profile = OpenAIModelProfile(
+            json_schema_transformer=OpenAIJsonSchemaTransformer,
+            openai_chat_supports_document_input=False,
+        ).update(base_profile)
 
         # For Qwen Omni models, force URI audio input encoding
         if 'omni' in model_name.lower():
diff --git a/tests/providers/test_alibaba_provider.py b/tests/providers/test_alibaba_provider.py
index 71d6ffdb8f..72cf620f9c 100644
--- a/tests/providers/test_alibaba_provider.py
+++ b/tests/providers/test_alibaba_provider.py
@@ -1,7 +1,9 @@
 import httpx
 import pytest
 
+from pydantic_ai import Agent
 from pydantic_ai.exceptions import UserError
+from pydantic_ai.messages import BinaryContent, DocumentUrl
 from pydantic_ai.profiles.openai import OpenAIModelProfile
 
 from ..conftest import TestEnv, try_import
@@ -9,10 +11,14 @@
 with try_import() as imports_successful:
     import openai
 
+    from pydantic_ai.models.openai import OpenAIChatModel
     from pydantic_ai.providers import infer_provider
     from pydantic_ai.providers.alibaba import AlibabaProvider
 
-pytestmark = pytest.mark.skipif(not imports_successful(), reason='openai not installed')
+pytestmark = [
+    pytest.mark.skipif(not imports_successful(), reason='openai not installed'),
+    pytest.mark.anyio,
+]
 
 
 def test_alibaba_provider_init():
@@ -64,6 +70,8 @@ def test_qwen_omni_profile_audio_uri():
     profile = provider.model_profile('qwen-omni-turbo')
     assert isinstance(profile, OpenAIModelProfile)
     assert profile.openai_chat_audio_input_encoding == 'uri'
+    # The document-input flag must survive the omni branch's `.update()` merge.
+    assert profile.openai_chat_supports_document_input is False
 
 
 def test_qwen_non_omni_profile_default():
@@ -92,3 +100,26 @@ def test_alibaba_provider_custom_base_url():
     provider = AlibabaProvider(api_key='test-key', base_url='https://custom.endpoint.com/v1')
     assert provider.base_url == 'https://custom.endpoint.com/v1'
     assert str(provider.client.base_url).rstrip('/') == 'https://custom.endpoint.com/v1'
+
+
+async def test_alibaba_document_input_not_supported(allow_model_requests: None):
+    provider = AlibabaProvider(api_key='test-key')
+    model = OpenAIChatModel(model_name='qwen-max', provider=provider)
+    agent = Agent(model)
+
+    with pytest.raises(UserError, match='alibaba.*does not support document input'):
+        await agent.run(
+            [
+                'Summarize this document',
+                BinaryContent(data=b'%PDF-1.4 test', media_type='application/pdf'),
+            ]
+        )
+
+
+async def test_alibaba_document_url_input_not_supported(allow_model_requests: None):
+    provider = AlibabaProvider(api_key='test-key')
+    model = OpenAIChatModel(model_name='qwen-max', provider=provider)
+    agent = Agent(model)
+
+    with pytest.raises(UserError, match='alibaba.*does not support document input'):
+        await agent.run(['Summarize this document', DocumentUrl(url='https://example.com/test.pdf')])