how · diff

git:20260924.ca7e47c to git:20260925.e15f2cb

1 added, 1 removed. Audit A to A.

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name: how

- description: "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. For motivation and history (why it is this way, why it was decided), use why."

+ description: "Use for \"how does X work\", \"X 는 어떻게 동작해\", \"이 구조 설명해줘\", code walkthroughs before changing something, and placement / ownership / layering questions (\"where should this live\", \"이건 어디에 둬야 해\", \"which package owns this\", \"is this the right layer\"). Explains subsystem architecture, runtime flow, onboarding mental models. For motivation and history (why it is this way, why it was decided), use why."

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# 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.

## Step 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. One explainer explores and explains in a single pass. Go to Step 2b.

- **Complex** (a subsystem spanning multiple files or services, a cross-cutting feature, a full architectural overview): spawn parallel explorers first, then hand off to the explainer. Go to Step 2a.

When in doubt, take the simple path.

## Step 2a. Explore (complex questions only)

Decompose the question into 2 to 4 exploration angles, each a distinct slice of the subsystem. Spawn all explorers in a single message:

- `subagent_type`: `Explore` (the built-in read-only explorer)

Each explorer gets the prompt in `references/explorer-prompt.md` with its angle filled in. Then go to Step 3.

## Step 2b. Direct Explain (simple questions)

Explore and explain it yourself in one pass, following the Instructions and Output Format in `references/explainer-prompt.md` (skip its explorer-findings parts). Go to Step 4.

## Step 3. Synthesize (complex questions only)

Once all explorers have returned, spawn one `Agent` subagent to synthesize their findings into one explanation. Synthesize once; do not re-run it per explorer:

- `subagent_type`: `general-purpose`

- `model`: `opus`

- Tell it in the prompt that it only reads and writes the explanation; it must not edit files.

Build its prompt from `references/explainer-prompt.md` with every explorer's findings filled in.

## Step 4. Present

Present the explainer's output to the user. 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.