Use for "how does X work", code walkthroughs before changing something, and placement / ownership / layering questions ("where should this live", "which package owns this", "is this the right layer"). Explains subsystem architecture, runtime flow, onboarding mental models. Use why for motivation.

How Explore the codebase to answer "how does X work?" questions. Produce architectural explanations at the level of a senior engineer onboarding onto a subsystem, enough to build a working mental model, not so much that it reads like annotated source code. Every spawn is a Task subagent with subagent type: generalPurpose and readonly: true . Explorers use the how explorer line in the pstack models.mdc rule (default grok 4.7 xhigh fast ), and every explainer uses the how explainer line (default claude opus 5 5 xhigh ). Set model to that line's value, or to the default if the rule or the line is missing. Leave model unset when the value is auto or inherit parent . If the Task tool rejects a slug, use the default and say so. If it rejects the default, use the closest valid slug of the same family from its error message. Pick each subagent's reasoning level and fast or standard speed for the job, per the Subagents section of the poteto mode skill. 1. Assess complexity If the scope is ambiguous, state your interpretation and explore. The user can redirect. Simple (a single module, a small utility, a narrow question such as "how does function X work"): no explorers. Spawn one explainer that explores and explains in one pass, built from references/explainer prompt.md without the explorer findings section. Go to step 4. Complex (a subsystem spanning multiple files or services, a cross cutting feature, a full architectural overview): go to step 2. When in doubt, take the simple path. 2. Explore (complex only) Decompose the question into 2 to 4 angles, each a distinct slice of the subsystem. Spawn all explorers in a single message, each with references/explorer prompt.md and its angle filled in. 3. Synthesize (complex only) Once all explorers have returned, spawn one explainer with references/explainer prompt.md and every explorer's findings filled in. 4. Present Present the explainer's output. Light edits for clarity or context from the conversation are fine. Do not substantially rewrite it. Output format The explanation uses the sections defined in references/explainer prompt.md , dropping any that do not apply: Overview, Key Concepts, How It Works, Where Things Live, Gotchas.