---
name: architect-impl-governance
description: "Partial Skill: invoke by name only"
user-invocable: false
metadata:
  actor: architect
  gate: impl
  compose: union
---

# Architect-Impl Governance — the structural-fit bar (impl gate)

The **Architect** bar at the **impl gate**: does the implementation fit the existing structure, and
is the suite's verification pyramid sound? Loaded by both faces. The SDD default for the `architect`
impl bar; a plugin may bind its own, and this loads when the registry leaves `architect`/`impl`
unbound.

## The bar

- **No knowledge duplication.** A rule, contract, or piece of logic has **one home** in the
  implementation; whatever needs it calls that home. Two copies of one piece of knowledge drift — a
  change lands in one and misses the other. But **coincidental resemblance is not duplication**: two
  units that look alike yet change for different reasons stay separate — a premature shared
  abstraction couples them, and the wrong abstraction costs more than the repetition. Test: does a
  change to one force the same change to the other? Only then converge.
- **No conflict.** The implementation does not contradict conventions, module boundaries, or a spec's
  contract — including the project's **declared** layout, judged as declared
  (`sdd:spec-structure-governance`). The declaration is not a licence: node <-> capability stays 1:1
  under every strategy, because the scheduler cuts one mission per node (ADR-0025). The two-level
  depth cap covers capability nodes; `design/` keeps its own shape — perspective files at the top and
  at most one version folder the placement map names for the next design.
- **Contained complexity.** Watch cyclomatic complexity and coupling; a unit hard to test is usually
  mis-structured — flag it.
- **A sound verification pyramid.** Across the suite the verification levels form a pyramid — a broad
  cheap base under a **thin e2e cap** that keeps the end-to-end path honest. An **all-e2e** suite is
  fragile and slow; a **capless** suite has no honesty check. The per-scenario level is the builder's
  call (`sdd:builder-impl-governance`); this bar judges the shape.
- **An orthogonal axis.** Structural fit judges a property the builder was not optimizing.
- **Structural concerns are deferred.** A structural problem in another capability spawns a new spec.

## Key points (read-check)

1. **No knowledge duplication** — one home per rule; but coincidental resemblance is not duplication
   (don't merge units that change for different reasons). No conflict; contained complexity.
2. **A sound verification pyramid** — cheap base, thin e2e cap; neither all-e2e nor capless.
3. **Per-scenario level is the builder's call; this bar judges the shape.**
4. **Structural concerns in another capability are deferred.**