# Architect First

> Settle types, module shape, and boundaries before implementation. Trigger: 'architect this', 'design module structure', 'settle types first'. For multi-module changes.

- Skill: `aryaminus/architect-first` (Agent Skill)
- Install (CLI): `npx skillmds@latest add aryaminus/architect-first`
- Raw SKILL.md: https://api.skillmd.com/api/skills/aryaminus/architect-first/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- License: Apache-2.0
- Author: aryaminus (https://skillmd.com/u/aryaminus)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/aryaminus/architect-first

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# Architect First

Settle types, module shape, and boundaries before writing code. Cheaper to fix the design now than rewrite callers later.

## Do NOT use when
- Single-function fix (use `tdd-bugfix`)
- Types are obvious and scope is narrow
- The change fits in one module with no boundary changes
- During implementation (design is already approved)

## Workflow

1. Search `ck_memory_search` for prior decisions about the affected area.
2. Investigate existing module boundaries (use `investigate` skill if needed).
3. Define:
   - **Types/structs** for key data structures
   - **Module boundaries**: owns / exposes / depends / does-not for each module
   - **Data flow**: trace primary use case across boundaries
4. Mark unresolved decisions as `[DECISION NEEDED]`.
5. Record design via `ck_memory_record` (type: `decision`).
6. Submit via `ck_review_submit` (review_type: `plan`, plan_phase: `design_options`). **Wait for approval**.

## Design principles

- Boundary discipline — modules own their data and invariants
- Type-system discipline — structs and typespecs, not bare maps
- Subtract before you add — can existing module absorb this?
- Minimize reader load — purpose clear from public API alone

## Output

- Types and structs
- Module boundary definitions
- Data flow for primary use case
- `ck_review_submit` plan awaiting approval
- `ck_memory_record` with the design