First-class invariant documents

[flyingrobots]

Migrated from Method backlog

This issue was created from a legacy filesystem backlog card. GitHub Issues are now the live work tracker; repository docs remain Method evidence.

Source backlog: docs/method/backlog/inbox/KERNEL_invariants-as-docs.md
Original lane: inbox
Original legend: KERNEL

Original backlog card

First-class invariant documents

bijou has docs/invariants/ with named invariants that legends and
design docs link to ("Layout Owns Interaction Geometry", "Commands
Change State, Effects Do Not"). Echo's invariants are scattered
across ADR prose and spec docs.

Extract them as standalone files so design docs can reference them
directly: "No Global State", "Two-Plane Law", "Canonical Merge
Equals Serial", "Deterministic Float Canonicalization".

[coderabbitai]

🔗 Related PRs

#309 - feat: add Doghouse PR flight recorder [merged]
#315 - feat(kernel): strand contract — cycle 0004 [merged]
#329 - Stack Witness 0001 fixture-backed jedit walking skeleton [merged]
#371 - feat(core): advance v0.1 contract evidence and retention [merged]
#388 - docs(method): add backlog cards and hook failure note [merged]

---

📝 Issue Planner

_{Check the box below or use the @coderabbitai plan command to generate an implementation plan and prompts that you can use with your favorite coding assistant.}

• Create Plan

---

🧪 Issue enrichment is currently in open beta.

You can configure auto-planning by selecting labels in the issue_enrichment configuration.

To disable automatic issue enrichment, add the following to your .coderabbit.yaml:

issue_enrichment:
  auto_enrich:
    enabled: false

💬 Have feedback or questions? Drop into our discord!