Design Invariants Skill

Audits a design proposal or diff against Exarchos-specific architectural invariants. Project-scoped — these invariants govern Exarchos itself, not consumers of the Exarchos plugin.

The skill is the operational complement to issue #1118 (codify principles) and #1109 (cross-cutting constraints). Reference content is also a candidate to back the v2.11.0 #1275 (MCP Resources) surface and the #1260 machine-readable invariants generator — every invariant carries a stable ID and structured shape.

When to use

• During /exarchos:ideate or /exarchos:plan, before committing a design.
• During /exarchos:review, alongside /axiom:audit.
• When reviewing a PR that touches the event store, MCP surface, runtime YAML, or composite tool registry.

When NOT to use

• For generic backend quality — use /axiom:* skills (see complementarity matrix below).
• For TDD / spec compliance — use /exarchos:review or the spec-review skill.
• For prose / AI-writing tells — use /axiom:humanize.

How to invoke