2026-05-04

Generative Ai, Llms, Regular-Expressions, Webassembly

Simon Willison — 2026-05-04#

Highlight#

Simon’s WASM-compiled Redis Array Playground is today’s standout, showcasing how quickly we can now spin up interactive sandboxes for in-flight C pull requests using AI agents like Claude Code.

Posts#

Redis Array Playground Salvatore Sanfilippo recently submitted a PR adding a new array data type to Redis. To try out the newly proposed commands, including a server-side ARGREP powered by the vendored TRE regex library, Simon utilized Claude Code to build an interactive WASM playground that runs a subset of Redis directly in the browser. The post also points to Salvatore’s own write-up on the AI-assisted development process behind the new array type.

2026-05-08

Blogs, AI, Tech

Html, Security, Prompt Engineering, Llms, Claude-Code

Simon Willison — 2026-05-08#

Highlight#

Simon re-evaluates his long-standing habit of asking LLMs for Markdown output, sparked by Anthropic’s Thariq Shihipar advocating for the rich capabilities of HTML. He tests this out practically by using his llm CLI to generate an interactive HTML explanation of a newly discovered Linux security exploit.

Posts#

[Using Claude Code: The Unreasonable Effectiveness of HTML] · Source Simon reflects on a piece by Thariq Shihipar (from Anthropic’s Claude Code team) that argues for requesting HTML instead of Markdown from Claude. While Markdown’s token-efficiency was a strict necessity during the 8,192-token GPT-4 days, modern LLMs can leverage HTML to output SVG diagrams, interactive widgets, and rich in-page navigation. Simon tests this technique by piping an obfuscated Python exploit from copy.fail into gpt-5.5 via his llm CLI tool, successfully prompting the model to generate a fully styled, interactive HTML explanation of the code.

2026-05-11

Blogs, AI, Tech

Coding Agents, Agentic-Engineering, Llms, Generative Ai

Simon Willison — 2026-05-11#

Highlight#

Today’s dispatches heavily focus on the macro consequences of the “agentic era” on the software industry, exploring everything from how coding agents are forcing massive corporate restructurings at GitLab to the stark mathematical reality of AI-generated codebase maintenance debt.

Posts#

GitLab Act 2 · Source Simon unpacks GitLab’s recent workforce reduction and structural flattening, which reorganizes their R&D into roughly 60 independent, empowered teams tailored for the agentic era. He highlights GitLab’s Jevons-paradox-inspired outlook: as AI agents collapse the cost and time of producing software, the overall market demand for software—and the builders who make it—will radically multiply. However, Simon pragmatically notes that GitLab has a strong financial incentive to project this optimism, given a recent 50% drop in their stock price and a business model heavily reliant on growing seat-based licenses.

2026-05-12

Blogs

Software Architecture, Domain Modeling, Conway's Law, Llms, Rust

Engineering Reads — 2026-05-12#

The Big Idea#

The defining characteristic of successful software isn’t just the syntax—it’s how the code rigorously models the human domain and how the architecture maps to the social incentives of its contributors. As we automate the mechanical aspects of programming, our primary engineering constraints shift toward capturing precise conceptual models and aligning system boundaries with organizational psychology.

Deep Reads#

What is Code · Unmesh Joshi · Source With LLMs increasingly generating our boilerplate, we are forced to re-evaluate what source code actually does. Joshi argues that code serves an intertwined dual purpose: it is both an execution instruction for a machine and a rigorous conceptual model of the problem domain. Programming languages act as vital thinking tools that shape how we reason about systems, not just as syntax to be emitted. As agentic coding tools become mainstream, building a precise domain vocabulary remains the critical bottleneck for communicating intent. Practitioners relying heavily on LLMs should read this to understand why deep domain modeling will outlive manual syntax generation.

2026-05-14

Blogs, AI, Tech

Datasette, Coding Agents, Generative Ai, Llms

Simon Willison — 2026-05-14#

Highlight#

The single most interesting theme today is the changing paradigm of programming languages from being a permanent “lock-in” to fungible, replaceable assets, driven by AI coding agents. Simon highlights this shift through Mitchell Hashimoto’s commentary on Bun’s recent language rewrite and a real-world anecdote of agent-assisted mobile app migration.

Posts#

[Not so locked in any more] · Source Expanding on thoughts about modern software architecture, Simon shares an anecdote from a recent conference about a tech company that used coding agents to rewrite their legacy iPhone and Android apps into React Native. The development team wasn’t overly concerned about committing to React Native, reasoning that if it turned out to be the wrong choice, the lowered cost of agent-driven development means they could just port it back to native code later. This underscores a major industry shift where programming language choices are increasingly no longer the permanent lock-in they once were.

2026-05-19

Blogs, AI, Tech

Llms, Gemini, Local Llms, Coding Agents, Llm-Pricing

Simon Willison — 2026-05-19#

Highlight#

Simon’s annotated PyCon US 2026 lightning talk provides a sharp, insightful retrospective on the “November 2025 inflection point,” identifying exactly when coding agents became reliable daily drivers and laptop-grade local models started wildly overperforming. It is a quintessential Willison post that perfectly frames the recent tectonic shifts in AI developer tooling.

Posts#

[The last six months in LLMs in five minutes] · Source Simon shares his annotated slides from a PyCon US 2026 lightning talk summarizing the past six months of LLM developments. He zeroes in on two main themes: coding agents crossing the threshold from “often-work” to “mostly-work” driven by Reinforcement Learning from Verifiable Rewards, and the astonishing capability of local models like the 20.9GB Qwen3.6-35B-A3B and Gemma 4. The post also tracks the recent surge of “Claws” (personal AI assistants running locally on Mac Minis) and features his ongoing “pelican riding a bicycle” SVG visual benchmark to compare models.

2026-05-20

Blogs, AI, Tech

Generative Ai, Prompt-Injection, Datasette, Gemini, Llms

Simon Willison — 2026-05-20#

Highlight#

Simon takes a critical look at Google I/O’s Gemini Spark announcement, digging into the opaque “Antigravity” stack and questioning how Google plans to mitigate prompt injection risks for a tool with deep access to user data. This highlights the growing industry tension between powerful workspace AI agents and fundamental security vulnerabilities.

Posts#

[Google I/O, Gemini Spark, Antigravity] · Source Sticking to his rule of only reviewing generally available tools, Simon breaks down the announcement of Gemini Spark, Google’s new OpenClaw competitor that natively integrates with Workspace apps. He notes a strange FAQ detail claiming Spark runs on “Antigravity”—a moniker applied to a desktop app, a Go-based CLI, and a VS Code fork. Crucially, Simon questions whether Google’s isolated VM approach and Agent Gateway will actually be enough to prevent an “agent security challenger disaster” when handling sensitive data via prompt injection. He also highlights that Google is deprecating its open-source Gemini CLI on June 18th in favor of a closed-source Antigravity CLI.

Simon Willison

Blogs, AI, Tech

Datasette, Llm, Css, Openclaw, Git, Open Source, Security, Ai, Gov-Uk, Birds, Birdwatching, Los Angeles, Pycon Us, Llms, Gemini, Local Llms, Coding Agents, Llm-Pricing, Generative Ai, Prompt-Injection, Sqlite, Sandboxing, Artificial Intelligence, Privacy, Memory, Advertising

Simon Willison — Week of 2026-05-16 to 2026-05-22#

Highlight of the Week#

The most impactful milestone this week is the official announcement of Datasette Agent, merging Simon’s three years of work on his LLM library directly into Datasette. This conversational AI interface allows users to naturally interrogate their databases, boasting an extensible plugin architecture for charts, image generation, and secure code execution.

Key Posts#

[The last six months in LLMs in five minutes] · Source Simon shared annotated slides from his PyCon US 2026 lightning talk capturing a major inflection point in AI developer tooling. He highlights how coding agents crossed the threshold to become reliable daily drivers, and points to the astonishing capabilities of massive local models running on consumer hardware like Mac Minis.