Anthropics February 2026 study classified 11 observable collaboration behaviors across 9,830 Claude conversations. After months of daily Claude Code use I wanted to know which of those 11 behaviors showed up in my sessions — and which ones never appeared.
The answer was uncomfortable. I was running three behaviors on repeat: decomposing tasks, specifying output format, providing context. The other eight barely registered.
skill-tree analyzes your Claude Code or Cowork session history, classifies all 11 behaviors against the Fluency Index baseline, and assigns you one of seven archetype cards rendered as tarot-style images with curated museum art. The live example at skill-tree-ai.fly.dev/fixture/illuminator shows what a full result looks like.
The part I want to explain is the growth quest mechanic, because it's doing something specific: it doesn't pick a behavior you're close to improving. It picks the behavior you avoid most. The logic is that if you're already fast at decomposing tasks, doing more decomposition doesn't expand your range — it deepens a rut. The Dakan & Feller 4D Fluency Framework (Description, Discernment, Delegation, Diligence) covers behaviors that don't compose neatly. Getting better at delegation looks nothing like getting better at discernment. So picking the furthest behavior, not the nearest, is the only way to break out of a local optimum.
The quest persists across sessions via a SessionStart hook so Claude Code surfaces it at the start of the next conversation — stored in ~/.skill-tree/ on Claude Code, $CLAUDE_PLUGIN_ROOT/.user-state/ on Cowork because Cowork's $HOME is ephemeral.
End-to-end analysis takes 30–60 seconds: find session files, extract user messages, remote classifier (Claude Haiku on Fly.io), archetype assignment, narrative synthesis, render, return a stable URL.
Install in Claude Code:
claude plugin marketplace add robertnowell/ai-fluency-skill-cards
claude plugin install skill-tree-ai@ai-fluency-skill-cards
Also available as an MCP server (npm install skill-tree-ai) for Cursor, VS Code, and Windsurf.