Simon Willison

Hello Python 3.15, goodbye 3.10, and now I can use 3.11

Python 3.15 introduces several new features, notably explicit lazy imports from PEP 810 that delay module loading until first use, and unpacking syntax in comprehensions (PEP 798) that simplifies flattening lists, sets, and dictionaries. The release also updates the profiling tools, renaming the tracing profiler to profiling.tracing and adding a new sampling profiler, profiling.sampling. These changes aim to improve performance and developer ergonomics in Python code.

Simon Willison
Aug 24

llm-anthropic 0.27

The release of llm‑anthropic 0.27 updates the Anthropic plugin for LLM to be compatible with the newly released anthropic v1.0.0 Python library, which has switched from httpx to httpx2. This mirrors a similar change made by OpenAI in their v3.0.0 release two weeks prior. The update includes a migration guide and a pull request that ensures tests pass after upgrading to anthropic>=1.

Simon Willison
Sep 1

Python 3.15.0 candidate 2 is here!

Python 3.15.0 candidate 2 has been released, marking the final release candidate for the upcoming 3.15 release scheduled for October. Hugo van Kemenade, the release manager, notes that only clear bug‑fix changes are allowed between this candidate and the final release, and urges third‑party maintainers to prepare wheels on PyPI and test their projects during this phase. The new RC is not yet available for GitHub Actions, but users can add it to their testing matrix using the allow‑prereleases and check‑latest flags to automatically test against the latest RC and then the stable release.

Simon Willison
Aug 25

EVE Online: The Move to Python 3 Begins!

EVE Online is beginning its transition to Python 3, a move that will involve using the futurize script on 2.4 million lines of code and a manual review of about 20,000 differences between Python 2 and Python 3. The company has historically run on Stackless Python since 2003, with the last major upgrade in 2010 to Stackless Python 2.7. While the announcement does not detail how Stackless will be replaced, the team previously showcased a shift away from Stackless in their Carbon engine for EVE Frontier, leveraging the open‑source carbonengine/scheduler library.

Simon Willison
Oct 10

Python 3.15.0 added to actions/python-versions

Python 3.15.0 has been added to the actions/python-versions repository. The author had been monitoring the repository for the release and used ChatGPT to automate the check. With the new version available, users can now include "3.15" in their GitHub Actions testing matrix to run tests against the latest Python release.

Simon Willison
Aug 31

Introducing wrapture

Introducing wrapture, a new Python library from Graham Dumpleton that extends the monkeypatching concepts of wrapt to support both testing and tracing simultaneously. It allows developers to wrap any function or method so that all accesses can be traced or overridden, serving as an alternative to unittest.mock and enabling observation of code without altering its behavior. Wrapture includes OpenTelemetry support and offers a configuration-based approach for adding tracing to existing projects, with the entire project and its documentation created under AI assistance.

Simon Willison
Aug 22

llm 0.33

The release of llm 0.33 introduces several key updates: it upgrades to the OpenAI Python library 3.x and switches the HTTP client from httpx to httpx2, adds comprehensive key handling for embedding functions, allows repeated template usage to combine configurations, and adds a reasoning_summary option for reasoning-capable responses. These changes improve compatibility, flexibility, and usability of the llm tool.

Simon Willison
Sep 11

Soft-deprecating re.match()

Python’s upcoming 3.15 release introduces a soft deprecation for the re.match() function, encouraging developers to avoid using it in new code. The function is now available under the clearer name re.prefixmatch(), which reflects its behavior of anchoring at the start of a string but not at the end. In most cases, re.search() or re.fullmatch() are recommended instead.

Simon Willison
Oct 13

web-edit 0.1a1

The article announces the release of web-edit version 0.1a1. It highlights performance optimizations that were written by Claude Opus 5.5, which were generated after feeding it a Python 3.15 profiling report created by GPT‑6 Astra. The release is tagged with "profiling" and "projects".

Simon Willison
Sep 18

Quoting Thariq Shihipar

The article announces that Claude Code will now support AGENTS.md files starting with version 2.1.277. If a CLAUDE.md file is absent in a folder, Claude will automatically look for and use AGENTS.md, leveraging Claude Code mods to customize the harness. The built‑in mod is available for use, and users can also create their own custom project instructions.

Simon Willison
Sep 22

llm-typesafe 0.1a0

Simon Willison released the llm-typesafe 0.1a0 plugin, adding support for TypeSafe AI’s Jev model to the LLM tool. Users install it with `llm install llm-typesafe`, set an API key, and can then ask Jev-model questions such as yes/no, choice, or scoring queries via the `llm -m jev` command. The release includes examples for each question type and references a README for further details.