pwasm 0.2a0 release adds near-full WASM spec support via AI-assisted updates

Simon Willison released pwasm 0.2a0, an alpha-stage pure-Python WebAssembly engine originally created in January as a side project during a period of intense AI experimentation. The project had remained untouched since its initial development.

To assess potential improvements, Willison used Claude Opus 5.5 to evaluate the current state of pwasm and identify steps needed to advance its functionality. The model was tasked with enabling MicroPython and micro JavaScript experiments from Willison’s research repository to run under pwasm, as well as identifying opportunities to speed up the engine.

Over 42 commits with minimal additional prompting, the updated engine now handles almost all of the WebAssembly specification. The release also bundles working WebAssembly builds of MicroPython, QuickJS, and Micro QuickJS in a PyPI wheel, enabling broader experimentation within the Python ecosystem.

Despite these technical achievements, Willison explicitly cautions against trusting the engine in its current alpha state, citing its experimental nature and the risks inherent in such early-stage software.