architect

name	architect
description	Sketch types, signatures, and module structure before code, then stay in the loop while implementation fills in. Use for /architect, 'architect this', 'design this', or non-trivial work where jumping to code would lock in the wrong shape.

Architect

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

Start

Use the environment's plan or task tracker with one entry per phase before starting. Autonomous mode without checkpoints needs visible phase position.

1. Ground
2. Sketch
3. Agree
4. Implement
5. Scrap

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. Critique mode if existing structure is the constraint or the design must push back on it.

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

Run the arena skill with the design-sketch task and the Phase A grounding artifacts. Pass references/runner-prompt.md as each runner's prompt. Each candidate produces a design package shaped per references/rationale-template.md: the caller's usage written first, then the type sketch, function signatures, module map, and prose rationale derived from it.

Use the available subagent pool. Prefer different model families when the host supports model selection; otherwise give each runner a distinct design constraint.

This makes brain/principles/exhaust-the-design-space.md concrete: whole-shape alternatives, not point fixes inside one shape.

Arena returns one synthesized design package. The synthesis decision populates 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.

The synthesis can ship as its own commit either way. Follow the scaffold-first guidance in brain/principles/foundational-thinking.md; subsequent commits fill bodies against a stable contract. Planned, scoped breakage during fill-in is acceptable under brain/principles/outcome-oriented-execution.md. For adversarial pressure before implementation, run interrogate on the synthesized sketch.

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. Surface it; don't bolt it on.

Phase E: Scrap when the architecture is wrong

If implementation keeps producing friction the sketch cannot absorb, throw the sketch out. Follow brain/principles/redesign-from-first-principles.md and brain/principles/fix-root-causes.md; do not bolt fixes onto a wrong design.

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. Surfacing deviations is Phase D's job; a repeated pattern of them is Phase E's trigger.

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. The rewrite signal is repeated friction of the same shape, not single hard cases.

When you scrap:

1. Re-run the how skill over what's been built. The implementation lessons enter the new design as inputs, not vibes.
2. Redesign as if the new constraints had been day-one assumptions, per redesign-from-first-principles.
3. Follow brain/principles/subtract-before-you-add.md. The new sketch should be smaller than the old one before it grows.
4. Return to Phase B and re-run arena.

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.