Scope — what a green check means

npx tsx src/cli.ts check examples/two-rooms.muro

✔ Consistent — 3 spaces / 3 boundaries
  Structural consistency only — architectural validity is what koyu validate says, separately

What that one line promises, and what it does not. That is this page.

The definition of green

For the structural tier and the interpreted tier, the declared invariants hold. About the carried tier it says nothing. About architectural validity it says nothing.

This is not a judgement but part of reading — the same layer at which a JSON parser rejects broken JSON.

Three domains

koyu is made of three domains. They are kept apart because the quality demanded of each is different.

Domain	What it holds	Size	Quality	Version
core	the language, its semantics, composition, identity, derivation, structural diagnostics, questions, canonical JSON	small	must be clean	freezes
validation	architectural judgement — fifteen rules	grows	may be messy	does not freeze
presentation and build	SVG generation and outside viewers	grows	may be messy	does not freeze

The dependency runs one way. Validation and presentation depend on core; core depends on neither. Core runs complete on its own. That one-wayness is enforced by a test, not by prose.

Not separating them makes two things happen at once — mess seeps into core and freezes there, and core's caution stops validation and presentation from growing. The separation itself is what makes it acceptable for the other two to be messy. Mess in a domain that does not freeze can be rewritten at any time, so it is cheap. Mess in a domain that freezes is permanent.

Even the types are separate. Core returns Diagnostic { code, severity }; validation returns Finding { rule, level }. Adding a judgement never moves the language version.

What is guaranteed

Guarantee	Diagnostics
Uniqueness of paths and identity	UID01–04 / ZON02 / duplicate-path errors during composition
Existence of referents	REF01 / undefined asset / the zone a polygon belongs to (SIT04)
Levels are defined	LVL01 / VRT02
Overlapping regions (in plan)	GEO01 / GEO02
Overlapping regions (in section)	HGT01 / HGT02
Composition resolves	composition errors
Sufficiency of what shape needs	SUF01–04
Soundness of relations	BND01–06 / VRT01–06
Uniqueness of derivation (openings, segs, lines, columns, run shapes)	OPN01–08 / SEG01–08 / LIN01–03 / COL01–02 / RUN01–05
Value domains of interpreted attributes	ATT01–03 / DAY01
Soundness of the givens	SIT01 / SIT02

Overlap in section belongs to core because it is the sectional case of overlap in plan. A ceiling below and a floor above occupying the same z is the same kind of contradiction as two space regions overlapping, and no single shape can be made from it. Architectural judgements about height — storey height, eaves height, setback envelopes — are not guaranteed; those are the validation face.

What is not guaranteed

Daylight, area ratios, floor area ratio, envelope continuity, whether a stair is climbable, whether a door can physically be installed, means of escape, street frontage — and every other question of architectural validity. Plus the meaning of carried-tier attributes.

None of these are absent. They are on another face — koyu validate holds them.

npx tsx src/cli.ts validate examples/two-rooms.muro

✔ Nothing caught by validation (this is a judgement, not a guarantee about the composition)

The output says so itself.

Do not claim "it works" because it is green

Green does not mean the building is usable.

Touching spaces default to a wall, so a two-storey building that declares not one door stays green and is completely sealed. The envelope does not grow by itself either — no default is derived against a space with no region (the exterior), so a forgotten boundary to the outside becomes a silent absence of wall.

Circulation is answered by koyu doors; judgement by koyu validate.

Questions do not say pass or fail

Core holds the questions of quantity and graph. It just never says pass or fail.

Question	What core returns	What validation says
Daylight	floor area and effective window area	whether it meets 1/7 (daylight.ratio)
Site	site area, frontage length, building area, total floor area and their ratios	2m of frontage (site.frontage), escape beyond the line (site.escape)
Vertical runs	riser count, riser, going, slope	whether it is cramped (stair.proportion), whether the slope is acceptable (run.slope)
Envelope	outline segments facing nothing	whether that is a hole (envelope.gap)
Circulation	the minimum-door route and passability	whether you can reach the outside (access.*)
Columns and openings	columns standing on grid intersections, openings on a segment	whether they collide (column.blocksdoor)

Thresholds belong to architecture. Neither 1/7 nor 2m nor 240mm is an invariant a composition must satisfy. Core returns numbers; validation draws lines through them.

The three attribute tiers

Tier	Examples	How core treats it
Structural	path, type, region, level, the other end of a relation, kind	always read. If it is broken, nothing is read
Interpreted	h w at daylight road site style …	the ledger defines the value domain, and core reads it
Carried	acme.sensor bems.temp survey.measured …	not read. Open, with a namespace

The carried tier carries a namespace (dot-separated). An unknown key without one is an error (ATT03) — so that a one-letter slip like heigh:2400 cannot silently do nothing. That is the only shape in which "not looked at" and "looked at and fine" can be told apart.

Without the declaration, they cannot be told apart, and "nothing wrong" in that state means nothing. Being able to carry something without judging it is a legitimate state, and saying so explicitly is the condition of that freedom.

Neighbouring pages

• Stability — what is promised not to break
• Identity — how far a uid guarantees anything
• What koyu does not hold — the resolution of this description
• koyu check — using the gatekeeper
• koyu validate — the judgement face
• Diagnostics — 65 codes
• Judgements — 15 rules