ADR-020 — Skill subsystem unification (SkillStore SPI) (v0.10)

Status

Accepted — SPI introduced in v0.10.0; physical module split + store implementations are follow-up.

Context

Skills exist in multiple shapes today:

• static skills (SkillDefinition + SkillRegistry)
• evolved skills (EvolvedSkill + EvolvedSkillStore)

This split makes “one skill lifecycle” harder to reason about for observability, policy, and persistence.

Decision

Add a minimal reactive SkillStore SPI in kairo-api:

• save/get/delete/list only (SPI Earned: no speculative operations)

Treat this as the convergence target for:

• static skill persistence adapters, and
• evolved skill persistence adapters

Consequences

• Pros: a single cross-cutting persistence abstraction for future governance/audit/OTel.
• Cons: requires a migration period; SkillRegistry remains until adapters exist.

Follow-ups

• Add kairo-skill module and relocate loaders/registry/tooling from kairo-core / kairo-tools.
• Provide default SkillStore implementation(s) and wire Spring auto-configuration.