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.

Each spawn below names a role from the pstack profile (written by /setup-pstack, always in your context). Spawn it with the profile's spawn recipe, passing that role's value as the model. A role with no line, or the value inherit, means no model override. If the harness rejects the model, retry with inherit and say so. With no profile in context, follow the fallback in the setup-pstack skill (references/profile-template.md) and tell the user once that /setup-pstack was not run.

Explorers use the how explorer role. Every explainer uses the how explainer role. access: read-only. run: foreground. 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)