ADR 0019: Personas ship as individual skills

Status

Superseded by 0036 — a standalone file becomes one carrier option for a profile (§27.1), not the only shipping form. The original decision text below is kept as history (Nygard, §30.1: an accepted ADR is never edited in place; only this status line is added).

Context

The persona catalogue describes 13 mindsets (docs/personas/). One option is to pack the canonical persona payloads into a single consolidated personas/SKILL.md. But that single file would force a consumer to load all personas to get any one of them, contradicting selective vendoring, and it would carry mindsets that duplicate a workflow skill — a "Builder" persona says little that write-feature doesn't already say.

With no always-loaded skills (0017) and activation by self-assessment (0020), each persona that ships needs its own directive description so the agent can load that mindset when the work calls for it — which a consolidated file cannot provide.

Decision

A persona ships as a standalone skill only when its mindset adds something beyond the matching workflow skill. By that test, 8 of the 13 mindsets ship as individual skills at /scaffold/.agents/skills/persona-<slug>/SKILL.md:

• persona-architect, persona-auditor, persona-janitor, persona-migrator, persona-performance-surgeon, persona-skeptic, persona-surveyor, persona-lead-engineer.

The other 5 mindsets do not ship as skills — each is carried by the matching workflow skill, where the mindset and the procedure are the same thing:

• Builder → write-feature; Bug Hunter → write-bug-report; Documentarian → write-documentation; Test Author → write-testing; Researcher → write-research.

Lead Engineer ships (persona-lead-engineer) precisely because it has no workflow skill — orchestration ships none — so the coordination mindset (disjoint-scope decomposition, the hand-off contract, liveness, verified merge) is the discipline and clears the bar. See 0025.

The docs/personas/ catalogue still documents all 13 mindsets and marks which 7 ship as skills. Each shipped persona body uses the fixed shape from 0013: Role / Mindset / Hard constraints / Forbidden actions / Red flags / Persona discipline.

Consequences

• Positive: a consumer vendors only the persona mindsets their work needs; each self-activates on its own description.
• Positive: no duplication between a persona and a workflow skill — the mindset lives in exactly one place.
• Negative: "13 mindsets, 8 skills" needs explaining so nobody hunts for a persona-builder skill — handled by the catalogue marking which mindsets ship and which ride a workflow skill.

Alternatives rejected

• Ship all 13 as persona skills. Five would be near-duplicates of their workflow skill, doubling the surface for no added discipline.
• Keep one consolidated personas/SKILL.md. Forces all-or-nothing loading and can't give each mindset the directive description that self-assessment activation depends on.

Ledger note (2026-06-11): partially superseded by ADR-0064 (persona shipping model).