# AEGIS — Security Knowledge Preservation Strategy

- **Document ID:** ARCH-42
- **Phase:** E.2 — Verification Methodology
- **Status:** Draft for review (post four-reviewer discipline)
- **Version:** 0.1
- **Date:** 2026-07-10
- **Owner:** Chief Security Architect

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## 1. Purpose

Codify how institutional knowledge remains intact as personnel change. Implements mandate #4. The premise: over 15 years, everyone who wrote v0 will leave; the platform must remain understandable, operable, and evolvable without them.

## 2. Principles

- **Nothing important lives only in a person's head.** If knowledge is not written down, it does not exist for the purpose of operations.
- **Docs-as-code.** Documentation is version-controlled, reviewed, and testable (mandate #43 Documentation Integrity).
- **Every "why" is recorded.** Rationale, not just decision, in ADRs.
- **Onboarding is a first-class product.** New engineers reach productivity on a documented path.
- **Rotation is normal.** Ownership rotation is expected; handoffs are structured.

## 3. Structured Knowledge Artifacts

- **ARCH-* corpus** — architecture ground truth.
- **ADRs** — decision rationale.
- **Runbooks** — operational procedures.
- **Playbooks** — response scripts (IR).
- **Threat model** — evolving adversary understanding.
- **Verification Matrix** — proof of properties.
- **Debt Register** — accepted compromises with reasoning.
- **Post-mortems** — incident learnings.
- **Ceremony recordings** — high-privilege operations.

## 4. Onboarding Path

- **Week 1.** Constitution + Principles + Vision + SRS + Threat Model.
- **Week 2–3.** Subsystem-specific ARCH-* + engine contracts.
- **Week 4.** Shadow an IR rotation + participate in a drill.
- **Month 2.** First contribution under mentor; first ADR authorship.
- **Month 3.** First code review on non-critical path.
- **Month 6.** First security-critical review under mentor.

## 5. Handoff Discipline

- **Owner change checklist.** Signed by outgoing owner + incoming owner + Auditor.
- **Areas covered:** open ADRs, pending Debt, upcoming ceremonies, escalation contacts, known-quirks (documented in "operator notes").
- **Handover session recorded** where possible.
- **Shadow period** — new owner shadows for at least 30 days.

## 6. Rotation Practices

- Security-critical subsystems: 18–24 month owner rotations.
- Rotation avoids single-point-of-knowledge but preserves depth (deputy stays).
- Post-rotation retro: what documentation was missing?

## 7. External Advisory

- Annual external CSA advisor review (per ARCH-34 §12) provides fresh eyes.
- External auditor reviews knowledge health (ARCH-23).

## 8. Knowledge Drift Detection

- **ARCH-* freshness metric** (ARCH-44) tracks doc age vs. code change rate.
- **Onboarding survey** after week 4: what was missing? Feed into docs.
- **"Explain this to a new engineer" drills** — during code review, reviewer asks author to explain rationale; failures become documentation gaps.

## 9. Retention Strategy for Departing Personnel

- Exit interview includes: what knowledge is at risk? what should be documented?
- Access revoked on schedule but knowledge documentation preferred *before* exit.
- Off-boarding runbook (ARCH-23) captures.

## 10. Independent Architecture Review

- **F-1.** *Docs-as-code discipline can decay.* Consistency checker (ARCH-41) + freshness metrics + reviewer checklist.
- **F-2.** *"Operator notes" section may hide tribal knowledge.* Encouraged; reviewed at handoff.

## 11. Adversarial Architect Review

- **A-1.** *Insider hoards knowledge for job security.* Culture + rotation + auditor visibility.
- **A-2.** *Attacker exploits knowledge gap during transition.* Deputy + shadow period + drilled runbooks.
- **A-3.** *Attacker corrupts docs during onboarding phase.* Docs-as-code + PR review + drift monitor.

## 12. Operational Reliability Review

- **O-1.** Onboarding measurable via time-to-first-contribution.
- **O-2.** Handoff artifacts machine-checkable (checklist completeness).
- **O-3.** 15-year sustainability: culture + process + tooling.

## 13. Self-Critique

- **S-1.** *"Culture" is fragile; tools + process cover partially.* Accepted; augmented by external review.
- **S-2.** *Rotation cost is real.* Budgeted; documented as ongoing operational investment.
- **S-3.** *Some knowledge (e.g., "why we didn't do X 5 years ago") is hard to preserve.* ADR "Alternatives Considered" section is the primary vehicle.

## 14. First-Target Analysis and Redesign

**Target:** the retirement of a founding CSA. Institutional memory concentration. **Response:** succession planning documented from day one; Deputy CSA rotated with real authority; ARCH-* corpus + ADRs are the truth (not the CSA); external advisor provides continuity.

## 15. Decisions

### D-42-1. Structured knowledge artifacts + drilled handoffs + rotation

- **Reason.** Mandate #4.

## 16. Change Log

- **0.1 (2026-07-10)** — Initial draft.