Version 2

Simon Willison published two posts on May 4, 2026, using Claude Code as an agentic rapid prototyping tool to explore emerging technical developments. In the first, he built a browser-based interactive playground running a WASM-compiled subset of Redis to demonstrate Salvatore Sanfilippo's proposed native array data type — a feature in an open PR that adds over 18 new commands[1]. In the second, he used Claude Code to build an experimental Python binding to the TRE regex library via ctypes and tested it against pathological ReDoS inputs, finding TRE significantly more robust than Python's standard re module due to its lack of backtracking[2].

Willison's posts illustrate a concrete use pattern for agentic coding tools: rapidly building just enough — a WASM playground, a ctypes binding — to make an unshipped or underexplored technology immediately tangible and shareable. The TRE finding also has practical security implications, pointing toward a production-usable alternative for Python applications that process untrusted regex input.

Simon Willison published two posts on May 4, 2026, each using Claude Code as an agentic rapid prototyping tool to make an emerging or underexplored technology immediately accessible.

The first post announced a browser-based interactive playground for a significant Redis feature still in development: a native array data type proposed by Salvatore Sanfilippo (antirez) in an open PR that adds more than 18 new commands[1]. Willison had Claude Code build the playground using a WASM-compiled subset of Redis, allowing users to experiment with the new array commands directly in the browser without any local install. He highlighted ARGREP — a command that runs server-side regex grep over array values using the TRE regex library recently vendored into Redis by antirez — as the most interesting of the new additions[1].

The second post followed from that same discovery. Curious about TRE's security properties after seeing it included in Redis, Willison used Claude Code to build an experimental Python binding to TRE via ctypes and tested it against pathological ReDoS inputs[2]. His finding: TRE handles those inputs significantly better than Python's standard library re module, primarily because TRE does not support backtracking — the mechanism most commonly exploited in regex denial-of-service attacks[2]. The ctypes binding and tests are explicitly experimental, intended to probe and demonstrate TRE's behavior rather than to ship as a library.

Across both posts, the framing is consistent: Claude Code functions as an agentic collaborator for rapid prototyping, building just enough — a WASM playground, a ctypes binding — to make nascent or obscure technology tangible and shareable. Neither artifact is presented as production-ready; their value lies in the exploration they enable and the findings they make concrete for an audience. Several Wikipedia articles on adjacent topics (Llama, 3D printing, Memex, regex engine comparisons, TRE, Jesse Vincent) have been surfaced as reactive background context by the pipeline but carry no substantive claims of their own.