Claude Code forgets everything between sessions, and its defaults are not a careful engineer's habits. developer-os is a free, MIT-licensed plugin that fixes both. Your agent searches an Obsidian vault before work and captures decisions into its inbox while it works; you approve what stays. Rules load in every session, skills cover specs, reviews, audits and PRs, and hooks ask before installs or force pushes. Plain Markdown, no server, no telemetry.