Simon Willison

MCP was always a bad idea?

Simon Willison
Sep 20

llm-keys-ui 0.1

The release of llm-keys-ui 0.1 introduces a plugin that allows users to manage API keys on remote machines without pasting them into the ChatGPT app. By running a simple command, the plugin provides a local or Tailscale URL for an interface where additional keys can be saved, and later retrieved via a shell command. This streamlines key management for coding agents used in LLM projects.

Simon Willison
Aug 19

Quoting Jeremy Morrell

My hypothesis is that there is a new opportunity for Extensible Software on the web . LLMs radically lower the cost of authoring extensions, and modern sandbox primitives lower the deployment cost and provide good security boundaries.

arXiv AI
Jun 2

Attested Tool-Server Admission: A Security Extension to the Model Context Protocol

arXiv:2605. 24248v2 Announce Type: replace-cross Abstract: The Model Context Protocol (MCP) standardizes how a large-language-model (LLM) agent and an external tool server exchange messages, but not trust: a host reads a server's self-declared tool list and dispatches calls, with no notion of which servers it may use, at what sensitivity, or which of a server's tools are in bounds.

By Alfredo Metere
arXiv AI
Aug 12

A Gateway Architecture for Enterprise MCP Authentication: Unifying Heterogeneous Auth, Identity Delegation, and the User / Non-User Persona Problem

arXiv:2608. 10760v1 Announce Type: cross Abstract: The Model Context Protocol (MCP) has become the de-facto interface for connecting LLM agents to enterprise tools, and adoption has been explosive: within a year, large organizations went from zero to dozens of internally built MCP servers.

By Suraj Kumar, Amy Wang, Srinivasan Manoharan
Simon Willison
Oct 22

Donating Agent Skills to the Agentic AI Foundation

Anthropic has announced that it will donate the Agent Skills standard to the Agentic AI Foundation (AAIF), a Linux Foundation‑backed organization co‑founded with Block and OpenAI. The move follows Anthropic’s earlier declaration that skills would be an open standard and aligns with the AAIF’s recent role as the home of the Model Context Protocol (MCP). The donation is part of Anthropic’s commitment to keeping Agent Skills community‑driven and vendor‑neutral.

Hugging Face Trending Papers
Jun 29

MCP Server Architecture Patterns for LLM-Integrated Applications

The Model Context Protocol (MCP), introduced by Anthropic in November 2024, defines a standardized interface for connecting large language models (LLMs) to external tools, data sources, and services. Within months of release, hundreds of community-built MCP servers appeared on GitHub, but no software-maintenance literature has yet described how the ecosystem is being structured in production.

Simon Willison
Oct 1

Quoting Matthew Green

The article discusses how two components—a payload that hijacks an agent and an agent that transports the payload—can combine to form a worm. It explains that agents running in isolated sandboxes can leave instructions in a shared package cache, altering each other's behavior. By substituting the package cache with communication channels like email, Slack, or WhatsApp and replacing sandboxed training runs with independently deployed personal agents such as Muse, the conditions necessary for a worm are met.

Simon Willison
Sep 17

Be alert: targeted attacks on prominent Rustaceans

The article warns of a targeted campaign against prominent Rust developers and crate owners, aiming to compromise their devices and accounts to publish malware. Attackers use seemingly legitimate video calls to trick targets into installing malicious software or executing commands, such as a fake audio codec or clipboard command. A recent supply‑chain attack on the array‑ref crate illustrates the threat, and the author suggests using dependency cooldowns as a defensive measure.