feat: add Foundry SDK

For more information, see:

https://aka.ms/foundry/claude/docs
https://docs.claude.com/en/docs/build-with-claude/claude-in-microsoft-foundry

Author: RobertCraigie

examples/azure.py

@@ -0,0 +1,26 @@
+# /// script
+# requires-python = ">=3.9"
+# dependencies = [
+#     "anthropic",
+# ]
+#
+# [tool.uv.sources]
+# anthropic = { path = "../", editable = true }
+# ///
+
+from anthropic import AnthropicFoundry
+
+cl = AnthropicFoundry(
+    resource="your-resource-name",
+    api_key="your-foundry-anthropic-api-key",
+)
+
+response = cl.messages.create(
+    model="claude-haiku-4-5",
+    messages=[
+        {"role": "user", "content": "Hello!"},
+    ],
+    max_tokens=1024,
+)
+
+print(response)

src/anthropic/__init__.py

@@ -101,6 +101,7 @@
 from .lib.tools import beta_tool, beta_async_tool
 from .lib.vertex import *
 from .lib.bedrock import *
+from .lib.foundry import AnthropicFoundry as AnthropicFoundry, AsyncAnthropicFoundry as AsyncAnthropicFoundry
 from .lib.streaming import *
 
 _setup_logging()

src/anthropic/_client.py

@@ -183,6 +183,10 @@ def default_headers(self) -> dict[str, str | Omit]:
 
     @override
     def _validate_headers(self, headers: Headers, custom_headers: Headers) -> None:
+        if headers.get("Authorization") or headers.get("X-Api-Key"):
+            # valid
+            return
+
         if self.api_key and headers.get("X-Api-Key"):
             return
         if isinstance(custom_headers.get("X-Api-Key"), Omit):
@@ -423,6 +427,10 @@ def default_headers(self) -> dict[str, str | Omit]:
 
     @override
     def _validate_headers(self, headers: Headers, custom_headers: Headers) -> None:
+        if headers.get("Authorization") or headers.get("X-Api-Key"):
+            # valid
+            return
+
         if self.api_key and headers.get("X-Api-Key"):
             return
         if isinstance(custom_headers.get("X-Api-Key"), Omit):

src/anthropic/lib/foundry.md

@@ -0,0 +1,127 @@
+# Anthropic Foundry
+
+To use this library with Foundry, use the `AnthropicFoundry` class instead of the `Anthropic` class.
+
+
+## Installation
+
+```bash
+pip install anthropic
+```
+
+## Usage
+
+### Basic Usage with API Key
+
+```python
+from anthropic import AnthropicFoundry
+
+client = AnthropicFoundry(
+    api_key="...",  # defaults to ANTHROPIC_FOUNDRY_API_KEY environment variable
+    resource="my-resource",  # your Foundry resource
+)
+
+message = client.messages.create(
+    model="claude-3-5-sonnet-20241022",
+    max_tokens=1024,
+    messages=[{"role": "user", "content": "Hello!"}],
+)
+
+print(message.content[0].text)
+```
+
+### Using Azure AD Token Provider
+
+For enhanced security, you can use Azure AD (Microsoft Entra) authentication instead of an API key:
+
+```python
+from anthropic import AnthropicFoundry
+from azure.identity import DefaultAzureCredential
+from azure.identity import get_bearer_token_provider
+
+credential = DefaultAzureCredential()
+token_provider = get_bearer_token_provider(
+    credential, 
+    "https://ai.azure.com/.default"
+)
+
+client = AnthropicFoundry(
+    azure_ad_token_provider=token_provider,
+    resource="my-resource",
+)
+
+message = client.messages.create(
+    model="claude-3-5-sonnet-20241022",
+    max_tokens=1024,
+    messages=[{"role": "user", "content": "Hello!"}],
+)
+
+print(message.content[0].text)
+```
+
+## Examples
+
+### Streaming Messages
+
+```python
+from anthropic import AnthropicFoundry
+
+client = AnthropicFoundry(
+    api_key="...",
+    resource="my-resource",
+)
+
+with client.messages.stream(
+    model="claude-3-5-sonnet-20241022",
+    max_tokens=1024,
+    messages=[{"role": "user", "content": "Write a haiku about programming"}],
+) as stream:
+    for text in stream.text_stream:
+        print(text, end="", flush=True)
+```
+
+### Async Usage
+
+```python
+from anthropic import AsyncAnthropicFoundry
+
+async def main():
+    client = AsyncAnthropicFoundry(
+        api_key="...",
+        resource="my-resource",
+    )
+    
+    message = await client.messages.create(
+        model="claude-3-5-sonnet-20241022",
+        max_tokens=1024,
+        messages=[{"role": "user", "content": "Hello!"}],
+    )
+    
+    print(message.content[0].text)
+
+import asyncio
+asyncio.run(main())
+```
+
+### Async Streaming
+
+```python
+from anthropic import AsyncAnthropicFoundry
+
+async def main():
+    client = AsyncAnthropicFoundry(
+        api_key="...",
+        resource="my-resource",
+    )
+    
+    async with client.messages.stream(
+        model="claude-3-5-sonnet-20241022",
+        max_tokens=1024,
+        messages=[{"role": "user", "content": "Write a haiku about programming"}],
+    ) as stream:
+        async for text in stream.text_stream:
+            print(text, end="", flush=True)
+
+import asyncio
+asyncio.run(main())
+```