Simon Willison — 2026-07-02#

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The standout update today is Simon’s release of a brand-new coding agent framework, llm-coding-agent 0.1a0, which he bootstrapped entirely using Claude Fable 5. It represents a significant step in evolving his popular llm library into a capable, tool-wielding agentic framework.

Posts#

llm-coding-agent 0.1a0 Simon released a new alpha tool that turns his llm library into a full-fledged coding agent. By prompting Claude Fable 5 in Claude Code to write the spec and build it via test-driven development, he shipped a CLI that includes file manipulation and command execution tools like edit_file and execute_command. He also highlights a neat Python API (the CodingAgent class) the AI implemented unprompted, and shared a successful test run where the agent built a SwiftUI ASCII time app using llm code --yolo.