fablize
A Claude Code plugin that adds Fable's verified working procedures, such as evidence-gated completion and systematic investigation, to Opus and other Claude models.
fablize is a Claude Code plugin developed after a controlled comparison between Fable 5 and Opus 4.8 across roughly 1,500 tool calls. The comparison found that on closed, answer-bearing work the two models performed about the same, and that the gap on open-ended work came from model capability rather than procedure.
The plugin applies only the procedures the comparison verified as transferable: grounding completion in actually running and observing the artifact, a multi-story completion gate that requires evidence before work counts as done, systematic investigation that moves from reproduction to hypotheses to a causal chain, and a deterministic hook that catches early stopping. Traits the comparison found to be model capability, such as open-ended creative judgment, are left alone; fablize tells the agent to escalate those instead of pretending to have them.