Agent Skills: research-precedent

Hunt for prior work and precedent — has this been done before, and does it apply to us? Searches three precedent sources in parallel: internal codebase (similar implementations to model after), the thoughts archive (prior tickets, decisions, plans, PRs), and external projects (open-source and documented industry patterns via web). Each precedent found is assessed for applicability — what matches our situation, what differs, and a factual transfer-fit class (directly-reusable / adaptable / informative / cautionary-anti-pattern) — then persisted as a precedent register. 'No precedent found' is a valid finding: it tells the caller the work is greenfield. When an external project warrants deep code study, recommends escalation to Scout External Codebase rather than cloning here. Mode-aware: interactive reviews the register; autonomous returns the register path. The right capability for 'has anyone built X before?', 'is there prior art for this pattern?', 'have we solved something like this?'.