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Security2026-06-07 · source-backed
On June 6, Willison released micropython-wasm, an alpha package that runs untrusted Python inside a WebAssembly binary with enforced memory, CPU, and file/network limits. He wired it into a Datasette Agent plugin, put GPT-5.5 xhigh inside, and challenged it to break out. So far it hasn't. Source: simonwillison.net This is the practical answer to the RCE story above. If your agent executes model-generated code, you need a sandbox, and renting a cloud VM per execution is slow and expensive. A 362KB container-free primitive you self-host is a different proposition. Worth a real look for anyone running code-execution agents.
Each link below shares sources, entities, or timing with this story.
Simon Willison released Datasette / Shared entities / Same source domain / What happened next
Linked by a graph relationship (Simon Willison released Datasette); both cover Python, Simon Willison, WASM, WebAssembly; reported by the same outlet (simonwillison.net).
Simon Willison uses Fable / Shared entities / Same source domain / What happened next / Tension
Linked by a graph relationship (Simon Willison uses Fable); both cover Python, Simon Willison, WebAssembly, Willison; reported by the same outlet (simonwillison.net).
Simon Willison uses Fable / Shared entities / Same source domain / Shared topic / What happened next
Linked by a graph relationship (Simon Willison uses Fable); both cover Python, Simon Willison, Willison; reported by the same outlet (simonwillison.net).
Linked by a graph relationship (Simon Willison uses Fable); both cover CPU, Python, Simon Willison; reported by the same outlet (simonwillison.net).
Simon Willison uses Claude Code / Shared entities / Same source domain / Shared topic / Earlier coverage
Linked by a graph relationship (Simon Willison uses Claude Code); both cover Python, Simon Willison, Willison; reported by the same outlet (simonwillison.net).
Simon Willison released Datasette / Shared entities / Same source domain / Shared topic / What happened next
Linked by a graph relationship (Simon Willison released Datasette); both cover Simon Willison, Willison; reported by the same outlet (simonwillison.net).
Simon Willison released datasette-agent / Shared entities / Same source domain / Shared topic / Earlier coverage
Linked by a graph relationship (Simon Willison released datasette-agent); both cover Python, Simon Willison, Willison; reported by the same outlet (simonwillison.net).
Simon Willison uses Claude Code / Shared entities / Same source domain / Shared topic / What happened next
Linked by a graph relationship (Simon Willison uses Claude Code); both cover GPT, Simon Willison; reported by the same outlet (simonwillison.net).