Anthropic SDK reaches v1.0.0 with httpx2 migration
Source published ·Modelwire updated
Original coverage: Simon Willison ↗·How Modelwire adds context
The development
Anthropic's Python SDK has reached v1.0.0, marking a significant infrastructure shift that mirrors OpenAI's recent v3.0.0 overhaul. Both libraries are migrating from httpx to httpx2, a dependency upgrade that affects the entire ecosystem of tools built atop these SDKs. Simon Willison's llm-anthropic plugin now provides compatibility with this new baseline, ensuring developers using the LLM CLI framework can continue working with Anthropic's models without friction. This standardization across major AI providers signals maturation in the Python tooling layer and reduces fragmentation for builders integrating multiple LLM backends.
Modelwire’s AI-generated summary of coverage from Simon Willison.
Modelwire analysis
Analyst takeOur AI-generated reading of the wider context and the next developments to watch.
The real story isn't Anthropic's v1.0.0 milestone itself, but that both Anthropic and OpenAI are converging on the same HTTP transport layer (httpx2) at the same time. This removes a technical reason for developers to favor one SDK over another.
This is largely disconnected from recent activity in the space, which has focused on model capability releases and safety research. Instead, it belongs to the infrastructure layer: the unsexy but critical work of standardizing how Python developers talk to LLM APIs. When competing vendors adopt the same underlying dependencies, it signals maturation and reduces switching costs. The fact that Simon Willison's llm-anthropic plugin had to ship compatibility updates shows the dependency upgrade wasn't backward-compatible, which means developers using older versions face a forced migration window.
If other LLM provider SDKs (Cohere, Together, Mistral) adopt httpx2 within the next two quarters, that confirms a genuine ecosystem standard forming. If they don't, or if they stick with httpx, that suggests the convergence is coincidental rather than coordinated.
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MentionsAnthropic · OpenAI · Simon Willison · llm-anthropic · httpx2 · anthropic-sdk-python
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Modelwire summarizes, we don’t republish. Simon Willison originally reported this story as “llm-anthropic 0.27”. The full content lives on simonwillison.net. If you’re a publisher and want a different summarization policy for your work, see our takedown page.