architect

Files (5)

• SKILL.md
• openai.yaml · agents/
• design-red-flags.md · references/
• rationale-template.md · references/
• runner-prompt.md · references/

SKILL.md (first lines)

# Architect

Design before implementing. Sketch types, function signatures, class shapes, and module boundaries with `not implemented` bodies and pseudocode. Compare viable shapes, then fill in code against the chosen sketch. If implementation proves the sketch wrong, throw it out and redesign.

## Phase A: Ground the problem

Build a real mental model of every system the new code touches. Run the **how** skill over the relevant subsystems.

Naming a file isn't grounding. Produce the traced model `how` prescribes. If the design redefines ownership or layering, also run the **why** skill on the existing shape so the rationale becomes a constraint, not a guess.

Skip Phase A only when the work is genuinely greenfield with no surrounding system to integrate.

## Phase B: Sketch

Use the Phase A grounding and `references/runner-prompt.md` to sketch the design yourself. Record the design package with `references/rationale-template.md`.

Design it twice. Require at least two structurally distinct candidates before synthesis, even when the first looks sufficient. This is the [exhaust-the-design-space](../principles/exhaust-the-design-space.md) reference made concrete. Whole-shape alternatives, not point fixes inside one shape.

Screen every candidate against [`references/design-red-flags.md`](references/design-red-flags.md) before synthesis. Reject or revise shallow modules, information leakage, temporal decomposition, pass-through methods, hypothetical seams, untestable dependencies, split ownership, two ways to do one task, importable internals, and hand-synced lists.

Assume the next contributor is an agent that sees only the files it opened, copies the nearest example, and takes the shortest path that compiles. Prefer the design where a change that looks right from one file is right for the whole repo. Judge each new abstraction by the wrong choices it removes from that agent, and pair it with a type, lint, or build failure that blocks any path around it.

Compare viable candidates on interface depth. Prefer the design that hides more complexity behind a smaller, simpler public surface. A rich interface can keep call chains short by concentrating capability instead of scattering it across layers.

Record the choice in the rationale's "Synthesis decision" section.

## Phase C: Agree (opt-in)

Default: proceed directly to implementation with the synthesized design. No human checkpoint.

Opt in to a checkpoint when the invoker explicitly asks: "architect with checkpoint," "stop and show me before implementing," or similar. Then surface the synthesized design and pause for sign-off.

For a planned rewrite, name verification boundaries per [outcome-oriented-execution](../principles/outcome-oriented-execution.md).

If the human pushes back on the shape (in a checkpoint or after the fact), treat that as Phase A evidence. Re-ground and re-run Phase B before writing more code.

## Phase D: Implement against the sketch

Replace `not implemented` bodies with code, pseudocode with logic. The synthesized sketch is the contract.

Deviations from the sketch are signal worth surfacing, not friction to absorb silently. If a function needs a parameter the sketch didn't anticipate, ask whether the sketch was wrong, the requirement was missed, or the implementation is overreaching.

## Phase E: Scrap when the architecture is wrong

If implementation keeps producing friction the sketch can't absorb, throw the sketch out. Don't bolt fixes onto a wrong design, per the [redesign-from-first-principles](../principles/redesign-from-first-principles.md) and [fix-root-causes](../principles/fix-root-causes.md) references.

The signal is a *pattern*, not single instances. Tells:

- The same shape of workaround appearing repeatedly across unrelated code.
- Multiple unrelated edge cases that all need special-case branches.
- Types that need escape hatches (`any`, casts, optional fields always set in practice) to compile.
- The "we need a lock" reflex when the sketch said the state wasn't shared.
- Callers having to know the abstraction's internal rules to use it.
- Two or more independent Phase D deviations of the same shape across the implementation.

Use judgment. A few edge cases don't condemn an architecture. Some problems are legitimately complex. Complexity in the data is not complexity in the design.

When you scrap:

1. Re-run the **how** skill over what's been built.
2. Redesign as if the new constraints had been day-one assumptions, per redesign-from-first-principles.
3. Subtract before adding, per the [subtract-before-you-add](../principles/subtract-before-you-add.md) reference. The new sketch should be smaller than the old one before it grows.
4. Return to Phase B and sketch again.

## Outputs

The caller's usage is written first and the type sketch derived from it. One file with new types and signatures for small changes. Module map plus type definitions for larger work. The rationale ships alongside, shaped per `references/rationale-template.md`, including the usage sketch and the synthesis decision.

From Camgineer/cstack, MIT.

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