Governance & the Solo Operator Model
SDD’s gates assume two pairs of eyes at every decision. The Solo Operator Model adapts those gates for the common case where there is only one human involved — without diluting the discipline.
The Self-Review Problem
Classical engineering process assumes gate owners cannot approve their own work. When one person is the PM, the architect, the implementer, the QA, and the ops lead, every gate is a self-review. The honest options are: give up on gating, fake the second reviewer, or find a different second pair of eyes.
SDD takes the third path. The "second eyes" are specialist AI agents that produce structured, patterned reviews at each gate. The human operator then provides documented judgment on the agents’ output — responding to each concern, accepting or rejecting the finding, with reasoning attached.
This is not a rubber stamp. The evidence of engagement is the written response to every agent concern.
Who Reviews What
| Gate | Pipeline Agent | Specialist Agents | Human Role |
|---|---|---|---|
| Spec Approval | sdd/pm-spec | marketing-copywriter (content specs)
| Confirm business intent, approve tier |
| Architecture Review | sdd/architect-review | architect-reviewer, penetration-tester | Review risks, confirm feasibility |
| QA Verification | sdd/implementer-tester | frontend-developer, qa-expert,
test-automator, code-reviewer | Verify test adequacy, manual checks |
| Deployment Authorization | sdd/deployment | (none currently) | Authorize release, confirm rollback |
Evidence Scales with Tier
| Tier | Evidence Required |
|---|---|
| Trivial | One-line rationale in the commit message. |
| Standard | Documented responses to agent concerns, inline in the spec or checklist. |
| Complex | Full written responses to every agent concern. |
| Critical | Full responses, a 24-hour waiting period, and an external second reviewer — mandatory, not optional. |
Escalation Rules
External review is mandatory for:
- Any Critical-tier spec (payments, auth, PII, core domain model)
- The first implementation of a new architectural pattern
- The annual pipeline audit
External review is recommended for any spec where the operator is uncertain after agent review, and for major framework or platform decisions.
Scope Discipline
Every feature needs its own spec. When scope creep happens inside a spec, it bypasses gates. The test: before starting implementation, ask "would a reasonable PM write a separate spec for this?" If yes, stop and write one. Bug fixes discovered during implementation are acceptable inline. Re-architecture is never acceptable inline.
Atrophy Prevention
A solo operator’s process degrades if left unexamined. SDD includes four standing disciplines:
- Weekly self-audit. Re-read one past approval. Would it convince a skeptic?
- Escape accountability. Trace every production issue back through the pipeline. Name where it should have been caught.
- Tier discipline. Track the tier distribution monthly. More than 80% Trivial is a signal that something is wrong.
- Learning events. Gate modifications get logged even when there is only one reviewer.