how

Files (3)

• SKILL.md
• explainer-prompt.md · references/
• explorer-prompt.md · references/

SKILL.md (first lines)

# 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.

Read [OpenCode runtime](../../references/opencode-runtime.md) for model preferences and delegation. Defaults inherit the parent; use independent workers only when available and permitted. Otherwise perform the scoped investigation directly and report the missing independent perspective.

## 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. Launch explorers within the available concurrency:

- `model`: the `how explorer` line, inherit the parent model unless configured
- Read-only assignment: inspect and report, with no edits or external writes.

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

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

Use one independent subagent when permitted that explores and explains in one pass:

- `model`: the `how explainer` line, inherit the parent model unless configured
- Read-only assignment: inspect and report, with no edits or external writes.

Build its prompt from [references/explainer-prompt.md](references/explainer-prompt.md) without the explorer-findings section. Go to Step 4.

## Step 3. Synthesize (complex questions only)

Once all explorers have returned, use an independent subagent when permitted to synthesize their findings into one explanation:

- `model`: the `how explainer` line, inherit the parent model unless configured
- Read-only assignment: inspect and report, with no edits or external writes.

Build its prompt from [references/explainer-prompt.md](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](references/explainer-prompt.md), dropping any that do not apply: Overview, Key Concepts, How It Works, Where Things Live, Gotchas.

From n3m6/opencode-config, GPL-3.0.

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