Use when a development task is unclear, multi-step, risky, or needs coordinated gates for shared understanding, research, parallel lanes, workflow artifacts, and verification. For a single concern, use the matching gate skill if available; for tiny mechanical changes, skip unless the user asks.
Use when development work has independent lanes for research, codebase exploration, inventory, validation, review, or non-overlapping implementation that can run in subagents, parallel tool calls, or separately owned workstreams.
Use when development work is large, risky, multi-session, multi-agent, interrupted, or needs durable plan/handoff memory for continuity across coding agents.
Use when development work depends on current or external facts: latest docs/APIs, library or platform behavior, security guidance, unfamiliar errors, migrations, comparisons, best practices, prior art, or known fixes.
Use when a development request is vague, exploratory, conflicted, under-specified, or the user says they are unsure, wants to be grilled, wants assumptions challenged, or needs goal, scope, constraints, and success criteria clarified before planning or implementation.
Use before saying development work is done, or when choosing project-shaped tests/checks to prove code behavior, bug fixes, refactors, config, infrastructure, or UI changes.
Pi-only web research workflow for environments that have pi-9router-ext and a subagent extension such as @tintinweb/pi-subagents configured. Use this skill when the user explicitly asks to use 9router, pi-9router-ext, ninerouter tools, or a 9router route/combo for web research, or when project/user instructions state that 9router-web-researcher is the preferred research stack. Do NOT use for ordinary web research in standard shared-mcp-only or non-Pi clients; use web-researcher instead. This skill always delegates research lanes to subagents and then synthesizes compact cited findings.
Pressure-tests any idea, plan, or decision through direct decision sparring until every branch is resolved — whether the question is "is this worth pursuing?" or "how do I execute this?" Activate when the user says things like "decision sparring", "spar with this decision", "interrogate my plan", "interrogate my idea", "stress-test this", "drill into this", "poke holes in it", "help me think through whether to pursue this", "I've decided to do X, help me think it through", "help me decide", or similar. Works on any domain - career moves, product launches, hiring plans, technical architecture, business decisions.