anhermon/pstack-claude/how

How

Claude Code: read Cursor terms in this skill through `claude-code/runtime.md` (tools, subagents, models, transcripts).

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.

Resolve each seat's explicit model and effort from delegation-kit's live routing table when its Delegation routing (live section is in context; otherwise use pstack-models.md and the defaults below. Map auto, inherit-parent, and inherit to model: sonnet, effort: medium. Always pass both parameters to Agent, including retries and resumes. For fan-outs of 3+ use sonnet/haiku seats, never opus. The main session owns final synthesis; any separately prescribed synthesizer runs alone after the fan-out.

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. The main session 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 synthesize in the main session. 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: pstack:read-only
• model: the how explorer line, default sonnet
• effort: explicitly pass the configured effort, default low
• read-only: enforced by pstack:read-only (no Edit/Write); still say "do not modify files" in the prompt

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)

The main session explores and explains directly; do not spawn an explainer. Follow references/explainer-prompt.md without the explorer-findings section. Go to Step 4.

Step 3. Synthesize (complex questions only)

Once all explorers have returned, the main session synthesizes their findings. Follow references/explainer-prompt.md with every explorer's findings filled in.

Step 4. Present

Present the main session's explanation 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.