Before resolving models or delegating, read T3 execution. It defines global configuration, capacity selection, and transport constraints.
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 below is a delegate_task with a self-contained brief; the child gets only the brief, never this conversation. Each brief says it is read-only: inspect only, no writes, no git commands. Resolve each role's model from pstack-models.md via orchestrator_capabilities. Never hardcode a slug. If the role line is missing, use the bundled default for that role.
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, mode: "async", model from the how explorer role.
Each explorer's brief is references/explorer-prompt.md with its angle filled in. Drain with task_status, then go to Step 3.
Step 2b. Direct Explain (simple questions)
Spawn one delegate_task that explores and explains in one pass, model from the how explainer role.
Build its brief from references/explainer-prompt.md without the explorer-findings section. Go to Step 4.
Step 3. Synthesize (complex questions only)
Once all explorers have returned, spawn one delegate_task to synthesize their findings into one explanation, model from the how explainer role.
Build its brief 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.