cursor__plugins/pstack/docs/guide/04-design.md

Design before you write code

One attempt at a hard design locks in the first shape the model thought of. These three skills exist so that doesn't happen. /architect settles types and boundaries before implementation. /arena runs several attempts in parallel and merges the best parts. /interrogate has other models try to break the result.

Settle the shape with /architect

/architect design the import pipeline before writing any code. i care most about how callers use it.

/architect grounds itself first, running /how over the code the design touches and /why when it moves ownership or layers. Then it runs /arena to produce competing design sketches, with the caller's usage written first in each, followed by types, signatures, and a module map.

By default it proceeds straight from the synthesized design into implementation. If you want to see the design first, say so:

/architect with checkpoint. stop and show me before implementing.

Fan out attempts with /arena

/arena take my prompt to the arena verbatim. i want to compare their proposals with yours.

/arena is the general tool underneath. N subagents attempt the same task in parallel, each writing to its own worktree or directory. A read-only judge, on a different model family when your configuration allows one, scores every candidate against a rubric. The coordinator reads each candidate end to end, picks a base, grafts in the best ideas from the losers, and verifies the result.

flowchart LR
    A[One task] --> B[Configured panel]
    B --> C[Candidate 1]
    B --> D[Candidate 2]
    B --> E[Candidate N]
    C --> F[Cross-judge]
    D --> F
    E --> F
    F --> G[Pick a base]
    G --> H[Graft the best parts]
    H --> I[Verify]

The panel comes from your /setup-pstack configuration, and you can adjust it per task. Ask for more candidates when the decision matters, fewer when it doesn't:

/arena this, 5 candidates. the cache key format is expensive to change later.

Break it with /interrogate

/interrogate the whole branch, but skeptically. no nitpicks unless it's an actual bug or regression.

/interrogate sends the same diff, intent, and rubric to several reviewers on different model families. Model diversity is the point. Different models have different blind spots, so a finding two models raise independently is high-confidence signal. The lead sorts everything into Act on, Consider, Noted, and Dismissed, with a reason for each dismissal, and applies nothing automatically.

Read the dismissals too. The lead is a pragmatic senior engineer, not an oracle, and you can override it.

How much design work does a task deserve?

You might be wondering whether every change needs this. No. Most changes need none of it. A rough ladder:

• A small, finished change you're unsure about needs /interrogate alone.
• A change that crosses function boundaries or moves ownership earns /architect, which brings /arena with it.
• A standalone decision where independent attempts would help, like naming, formats, or an algorithm, is /arena directly.
• A contested design that's expensive to reverse gets /architect, then /interrogate before shipping.

/poteto-mode already applies this ladder. Boundary-crossing work triggers /architect on its own, so you reach for these directly mainly when you want more or less scrutiny than the default.

Next: Build and clean the change.