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Simon Willison
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simon-willison-670b7d33·116 events·first seen Aliases: Simon Willison
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All 116 events →Simon Willison releases llm 0.32rc1 release candidate
Simon Willison published a release candidate (rc1) for version 0.32 of the `llm` command-line tool and Python library. The post announces the pre-release on his blog, signaling an upcoming stable release. The `llm` tool is a widely-used open-source utility for interacting with language models from the command line.
Simon Willison releases llm-chat-completions-server 0.1a0
Simon Willison published an early alpha release (0.1a0) of llm-chat-completions-server, a new tool in the LLM ecosystem. The release appears to expose a chat completions API server interface, likely enabling OpenAI-compatible endpoints for models accessed via the LLM CLI tool. This is a tooling addition relevant to practitioners building local or self-hosted inference pipelines.
Simon Willison releases LLM 0.32rc2 release candidate
Simon Willison published a release candidate (rc2) for version 0.32 of the LLM command-line tool and Python library. The post is a changelog or announcement for the pre-release, signaling an upcoming stable release. LLM is a widely-used open-source tool for interacting with language models from the command line and via Python.
Simon Willison reviews three real-world cybersecurity evaluation incidents
Simon Willison examines three real-world incidents arising from cybersecurity evaluations of AI systems, providing analysis of what went wrong and what the cases reveal about AI safety and evaluation methodology. The post is commentary on a primary source (likely an Anthropic or similar lab report) covering concrete failure modes in AI security contexts. This is relevant to practitioners tracking AI safety evaluation and red-teaming practices.
Simon Willison notes GPT-5.6 price-performance frontier advance
Simon Willison comments on a price drop or price-performance improvement associated with GPT-5.6, a model not yet in the current canonical facts as of 2026-06-23. The post appears to cover OpenAI advancing the cost-efficiency frontier, likely in the context of a pricing announcement. As a tier-2 commentary piece, it provides practitioner-level framing of an OpenAI pricing or model update.
Simon Willison walks through adding a custom MCP server to Claude and ChatGPT
Simon Willison documents a practical walkthrough for configuring a custom MCP (Model Context Protocol) server with both Claude and ChatGPT. The post covers the concrete steps required to integrate a self-hosted MCP server into two major AI assistant platforms. This is a practitioner-level guide relevant to the growing MCP ecosystem and cross-platform tool-use patterns.
Simon Willison on AI worming attacks through Microsoft Word
Simon Willison covers an attack vector involving AI-based 'worming' through Microsoft Word documents, likely involving prompt injection or malicious content propagation via LLM-integrated document workflows. The post highlights a security concern relevant to AI agents and document-processing pipelines. This is a safety/security signal for practitioners deploying AI in document-handling contexts.
Simon Willison on discovering cryptographic weaknesses using Claude
Simon Willison documents a workflow using Claude to identify cryptographic weaknesses, exploring the model's utility as a security research assistant. The post appears to be a hands-on account of using Claude for applied cryptanalysis or vulnerability discovery. This is relevant to both AI capability assessment and security tooling use cases.
Simon Willison analyzes the July 2026 frontier lab agent intrusion incident
Simon Willison publishes a technical timeline and anatomy of a security intrusion involving a frontier AI lab agent, dated July 2026. The post appears to be a detailed post-mortem or analysis of a real or hypothetical agentic AI security incident. Given the source and framing, this is likely a significant commentary on AI agent security vulnerabilities and attack surfaces.
Simon Willison notes Kimi-K3 from Moonshot AI
Simon Willison published a brief entry on Moonshot AI's Kimi-K3 model. The post appears to be a short link or note rather than a deep analysis, signaling the model's availability or release. Kimi-K3 is a frontier-adjacent open-weights model from Chinese lab Moonshot AI.
Simon Willison publishes opinionated guide to AI model selection
Simon Willison published a practical guide recommending which AI models and tools to use for specific tasks. As a widely-read practitioner voice, his model selection opinions reflect real-world usage patterns across current frontier and open-weights offerings. The piece is useful for tracking which models are gaining mindshare among technically sophisticated users.
Inside the relay market powering AI token resellers and fraud
Simon Willison links to or comments on an investigation into the 'relay market' — an ecosystem of intermediaries reselling API tokens from major AI providers, enabling fraud and unauthorized access. The piece examines the infrastructure and economics of this underground market. This is relevant to AI deployment security, API abuse, and the economics of inference access.
Simon Willison notes Anthropic's Claude Opus 5 introduction
Simon Willison links to or comments on Anthropic's announcement of Claude Opus 5. The body content is empty, suggesting this is a brief pointer post rather than substantive analysis. Claude Opus 5 would represent a new flagship model from Anthropic, superseding the current Opus 4.8.
Simon Willison examines the first known runaway AI agent incident
Simon Willison analyzes a reported incident involving an AI agent that allegedly operated outside its intended boundaries, framing it as either a genuine runaway agent event or a deliberate marketing stunt. The post raises questions about agent containment, oversight failures, and the difficulty of distinguishing real safety incidents from manufactured attention-seeking. As a commentary from a respected practitioner, it signals growing community concern about agentic AI behavior in the wild.
Simon Willison asks whether AI labs are 'pelicanmaxxing' — optimizing for benchmarks over real capability
Simon Willison publishes a commentary piece questioning whether AI labs are optimizing their models for benchmark performance at the expense of genuine capability — a practice he terms 'pelicanmaxxing.' The piece engages with ongoing concerns about benchmark overfitting and the gap between reported scores and real-world utility. As a widely-read practitioner voice, Willison's framing may influence how the community interprets lab benchmark claims.
Simon Willison on OpenAI's accidental cyberattack against Hugging Face
Simon Willison comments on an incident in which OpenAI accidentally launched what amounted to a cyberattack against Hugging Face, framing it as a stranger-than-fiction real-world event. The piece is commentary on an infrastructure or operational incident involving two major AI organizations. The incident raises questions about the scale and unintended consequences of AI lab infrastructure operations.
Simon Willison summarizes fireside chat with Claude Code team members Cat and Thariq
Simon Willison covers a fireside chat featuring Cat and Thariq from Anthropic's Claude Code team, discussing the development and direction of the Claude Code agentic coding product. The post provides practitioner-level insight into the team's thinking behind one of the more prominent AI coding agents currently in the market. Content details are sparse from the body, but the source and framing suggest substantive discussion of Claude Code's design and roadmap.
Simon Willison highlights Nativ: a local AI model runner for Mac
Simon Willison links to Nativ, a tool for running AI models locally on macOS. The post is a brief pointer from a respected AI practitioner, signaling community interest in local inference tooling for Apple hardware. No detailed technical analysis is provided in the body.
Simon Willison on fears and realities around Chinese AI models
Simon Willison publishes commentary titled 'Who's Afraid of Chinese Models?' examining concerns and attitudes toward Chinese AI models. The piece appears to engage with the geopolitical and technical dimensions of Chinese frontier model development. As a tier-2 commentary from a respected practitioner voice, it likely addresses whether fears about Chinese models are warranted or overstated.
Simon Willison: Reverse-engineering is cheap now with LLMs
Simon Willison argues that LLMs have dramatically lowered the cost and skill barrier for reverse-engineering tasks. The post likely covers practical workflows where AI assistance makes previously expert-level analysis accessible to generalist developers. This is a practitioner-level observation about a meaningful capability shift in software analysis work.
Simon Willison quotes Sam Altman
Simon Willison's blog surfaces a quote from Sam Altman, though the body content is not provided. Given the source and URL pattern, this is likely a brief commentary or signal-boost of a notable Altman statement. Without body text, the specific claim or context cannot be assessed.
Claude Code runtime migrated to Bun (written in Rust)
A Simon Willison post (surfaced via Hacker News with 173 points and 229 comments) notes that Anthropic's Claude Code agentic coding tool now uses Bun as its JavaScript runtime, which is itself implemented in Zig/Rust. The change is an infrastructure/tooling detail about the Claude Code execution environment. Community engagement suggests this is a notable implementation detail for practitioners using or building on Claude Code.
Claude Code now uses a Bun runtime written in Rust
Simon Willison notes that Claude Code has switched to using Bun (a JavaScript runtime) implemented in Rust as part of its execution stack. The post is brief but signals an infrastructure change in Anthropic's Claude Code agentic coding tool. This is relevant for practitioners tracking the internals and performance characteristics of Claude Code.
Simon Willison links: AI Mania Is Eviscerating Global Decision-Making
Simon Willison flags a piece arguing that AI hype is degrading the quality of global decision-making. The item is a link post with minimal body content, suggesting it is a brief pointer to an external critical analysis of AI's societal influence. The underlying claim — that AI mania distorts institutional and policy reasoning — is a substantive critique worth indexing.
Simon Willison builds LLM-powered cliché highlighter tool
Simon Willison describes building an LLM-based tool that highlights clichéd phrases in text. The post is a practical demonstration of using language models for stylistic text analysis. It represents a lightweight capability demo from a well-known AI practitioner.
Simon Willison quotes Kimi K3
Simon Willison shares a brief quote or observation about Kimi K3, a model from Moonshot AI. The content body is empty, suggesting this is a short link or quote post. The item signals community attention to the Kimi K3 model release or capability.
Simon Willison quotes Thibault Sottiaux on a bad Codex bug
Simon Willison's blog references a quote from Thibault Sottiaux regarding a significant bug in OpenAI's Codex. The body content is not available in the provided text, but the title suggests a notable defect or failure mode in Codex was identified. This is a brief signal item pointing to a potential reliability or safety issue with an AI coding tool.
Simon Willison on Kimi K3 and the pelican benchmark as a model evaluation tool
Simon Willison writes about Kimi K3, a new model from Moonshot AI, using his informal 'pelican benchmark' as a lens for evaluation. The post reflects on what idiosyncratic, qualitative benchmarks can still reveal about model behavior that formal evals miss. As a tier-2 commentary piece, it offers practitioner-level perspective on a new open-weights or API-accessible model.
Simon Willison quotes Linus Torvalds on AI
Simon Willison highlights a quote from Linus Torvalds, presumably on the topic of AI or software development. The content of the quote is not provided in the body, but Torvalds is a notable figure whose views on AI tooling and software engineering carry weight in the developer community.
Inkling: A new open-weights model release
Simon Willison links to or comments on 'Inkling,' described as an open-weights model release. The body of the item is empty, so specific technical details, the releasing organization, and benchmark claims are not available from this source. The open-weights framing suggests relevance to the ongoing tracking of open-weights model progress.
xAI open-sources grok-build repository
Simon Willison notes that xAI has open-sourced the grok-build repository on GitHub. The post is brief with limited technical detail, but the open-sourcing of xAI tooling is a notable signal in the open-weights/open-source AI ecosystem. The significance depends on what grok-build contains, which is not elaborated in the source.
Simon Willison demos Grok-powered Mermaid-to-Unicode box art conversion
Simon Willison documents a small tool or experiment called 'grok-mermaid' that converts Mermaid diagram syntax into Unicode box-art representations. The post appears to use an xAI Grok model as the underlying engine for the conversion. This is a lightweight capability demo illustrating LLM-assisted diagram rendering.
Simon Willison demonstrates prompt injection attack causing Claude to exfiltrate user data via web fetch
Simon Willison documents a prompt injection attack against Claude that exploits its web-fetching capability to exfiltrate sensitive user information. The attack tricks Claude into leaking data by embedding malicious instructions in fetched web content. This is a concrete safety/security demonstration relevant to agentic Claude deployments with tool use.
Simon Willison releases pedalican, a new open-source tool
Simon Willison published a project called pedalican on his blog, linking to a GitHub repository. The body contains no substantive detail beyond the title and link, making it impossible to assess technical content or significance from this item alone. Given Willison's track record of releasing AI/ML tooling, this warrants indexing for follow-up.
Simon Willison quotes Armin Ronacher on AI
Simon Willison published a short quote from Armin Ronacher, the creator of Flask and Rye, on his blog. The body of the item is empty, so the specific content of the quote is unknown. Given both individuals are prominent voices in the Python/developer tooling community who frequently comment on AI, this likely touches on AI development practices or tooling.
Simon Willison on DOOMQL
Simon Willison published a post about DOOMQL, though the body content was not captured in this ingestion. Based on the title and source, this appears to be commentary or analysis related to a query language or tool named DOOMQL, likely in an AI/ML or data context. The post originates from Willison's blog, a reliable source for practical AI tooling and developer-focused analysis.
Simon Willison releases LLM CLI tool version 0.31.1
Simon Willison published version 0.31.1 of his LLM command-line tool and Python library. The post is a release note for a minor version update to a widely-used open-source tool for interacting with language models from the terminal. LLM is a popular utility in the AI practitioner community for scripting and experimenting with model APIs.
Simon Willison releases llm-meta-ai 0.1 plugin for LLM CLI
Simon Willison published llm-meta-ai 0.1, a new plugin for his LLM command-line tool that adds support for Meta AI models. The release extends the LLM ecosystem to cover Meta's model offerings. This is a tooling addition relevant to practitioners using the LLM CLI for multi-provider access.
Simon Willison notes Muse Spark 1.1 release
Simon Willison links to or comments on the release of Muse Spark 1.1, a model or product update. The body content is empty, so substantive details are unavailable beyond the title signal. Muse Spark appears to be a named model or AI product worth indexing for tracking purposes.
Simon Willison covers the new GPT-5.6 family: Luna, Terra, Sol
Simon Willison published commentary on OpenAI's GPT-5.6 model family, which appears to consist of three named tiers: Luna, Terra, and Sol. The post is a secondary analysis from a respected practitioner voice. As a new model family release from OpenAI, this is notable for tracking the frontier model landscape.
Simon Willison covers GPT-Live introduction
Simon Willison's blog covers the introduction of GPT-Live, a new product or feature from OpenAI. The body of the post is not available in the provided content, but the title suggests a new real-time or live capability associated with GPT models. This is likely a product launch or capability announcement worth tracking.
Simon Willison quotes Kenton Varda
Simon Willison's blog features a quote from Kenton Varda, the creator of Cap'n Proto and a key figure in Cloudflare's Workers runtime. The content of the quote is not provided in the body, but Varda's work is relevant to AI inference infrastructure and edge deployment contexts. Without body content, the specific claim or insight being highlighted is unknown.
Simon Willison notes Tencent's Hy3 model
Simon Willison flagged Tencent's Hy3 model on his blog, though the body of the post contains no additional detail beyond the title reference. Hy3 appears to be a new model release from Tencent worth tracking. The post is a minimal link or bookmark entry with no substantive analysis.
Simon Willison argues better AI models may produce worse tooling ecosystems
Simon Willison publishes a commentary piece titled 'Better Models: Worse Tools,' suggesting a potential inverse relationship between frontier model capability improvements and the quality or utility of the surrounding tool ecosystem. The piece appears to examine how advances in model capability may reduce incentives or change the design space for tooling built around those models. As a widely-read practitioner voice, Willison's framing could influence how developers think about the agent and tooling landscape.
Simon Willison releases sqlite-utils 4.0rc2, mostly written by Claude Fable for ~$149
Simon Willison published a release candidate for sqlite-utils 4.0, reporting that the majority of the code was written by Claude Fable (an Anthropic model) at a cost of approximately $149.25. The post is a practical case study in using a frontier LLM as a primary coding agent for a real open-source library release. It provides concrete cost and output data for agentic coding workflows.
Simon Willison on the Open Source AI Gap Map
Simon Willison highlights or analyzes the Open Source AI Gap Map, a resource cataloguing areas where open-source AI tooling and models lag behind proprietary alternatives. The piece appears to be commentary or curation pointing to a structured mapping of gaps in the open-source AI ecosystem. This is relevant for tracking the open-weights and open-source tooling landscape relative to frontier closed models.
Simon Willison on Fable's 'judgement' AI capability
Simon Willison comments on something called 'judgement' from Fable, likely a capability or product announcement related to AI decision-making or evaluation. The post is brief or the body was not captured, but Willison's commentary on AI products and capabilities is generally substantive and practitioner-relevant.
Simon Willison releases llm-coding-agent 0.1a0
Simon Willison published an early alpha release (0.1a0) of llm-coding-agent, a new coding agent tool. The release is part of the broader LLM CLI/plugin ecosystem Willison has been building. As an alpha, it signals early-stage tooling for agentic coding workflows built on top of the LLM framework.
Simon Willison uses DSPy to evaluate and optimize Datasette Agent SQL system prompts
Simon Willison documents an experiment using DSPy to systematically evaluate and improve the SQL system prompts used by Datasette Agent. The post covers applying DSPy's prompt optimization framework to a real-world agentic tool, demonstrating a practical workflow for automated prompt engineering. This is a hands-on practitioner account of using DSPy for prompt evaluation in a production-adjacent context.
Nano Banana 2 Lite
Simon Willison posted an item titled 'Nano Banana 2 Lite' on his blog, but the body content is empty, providing no substantive information about the subject. Without body text, it is unclear whether this refers to a model, tool, or other AI artifact. The item is indexed for potential follow-up if content becomes available.