/first-principles-review

name: first-principles-review
description: "Use when asked for first-principles or Occam's-razor review, or when high-risk decisions involve competing constraints, fallback growth, duplicate owners, or architecture direction risk. Ordinary bug fixes stay on the fast path."

First Principles Review

Purpose

Use this as a lightweight decision review before another Aegis workflow makes a directional choice. It is a compositional skill, not a standalone workflow.

Do not replace `brainstorming`, `systematic-debugging`, `writing-plans`, `requesting-code-review`, or `verification-before-completion`. Use it to clean the decision surface those skills will act on.

When this review materially changes the direction, surface `Aegis Visibility` in natural prose: name the first principle, dropped assumption, smallest sufficient path, or owner / retirement falsifier that changed the decision. Keep it advisory and task-specific; do not turn the lens into approval authority or a generic skill trace.

Use When

• The user asks for first principles, first-principles thinking, or Occam's

razor.

• A design, plan, or fix has multiple plausible paths and unclear selection

criteria.

• The task has ambiguous goals, competing constraints, or product/architecture

direction risk.

• Debugging is drifting into repeated fixes, fallback growth, duplicate owners,

consumer-side patches, or "just add another branch" reasoning.

• A review finds that the implementation may be locally correct but directionally

wrong.

Do Not Use

• Simple Q&A, status checks, tiny wording/config edits, or clearly bounded

single-owner changes.

• Mechanical execution of an approved plan unless a new directional conflict

appears.

• As a required step for every task, every turn, or every TDD cycle.

Five-Line Review

Answer only what is needed, usually in five short lines:

First Principle: What irreducible outcome must this satisfy?
Non-negotiables: What constraints cannot be broken?
Assumptions to Drop: What is habit, inherited shape, or unproven preference?
Smallest Sufficient Path: What is the least complex path that satisfies the first principle?
Escalation Signal: What finding would require spec/design/architecture review?

When the direction depends on a new mechanism or an unfamiliar domain, insert one optional line between path and escalation:

Known Prior Art: proven external pattern worth adopting or adapting to project
constraints (cite source), or `unknown` when precedent cannot be verified here

For repair choices, "smallest" means smallest sufficient stable repair, not the smallest textual diff:

Minimality Check:
- Smallest textual diff:
- Correct owner:
- Bug class fixed:
- New branch/fallback added:
- Old path retired or scheduled:
- Verdict: sufficient repair | local patch | needs first-principles review

Decision Hygiene Review

Use this escalation only when a design, fix, or plan needs endorsement before it is written into a spec or implementation plan.

Escalate from the five-line review when any of these risk signals appear:

• multiple plausible paths and no clear selection criteria
• a new owner, duplicate owner, fallback, adapter, or compat-only carrier
• an old path that may need delete-first handling or a retirement trigger
• an unverified assumption that the proposal depends on
• user language such as "more elegant", "long-term stable", "first

principles", or "Occam"

• a plan could encode the wrong owner, abstraction, compatibility boundary, or

retirement schedule

• an existing object, behavior, responsibility, contract, or relationship may

be reinterpreted, narrowed, replaced, or retired, and the proposal could lose a legitimate role or explicit reference while removing invalid authority

Use this compact shape:

First-principles invariants:
- Non-negotiable goal:
- Non-negotiable constraints:
- Historical assumptions to delete:

Bounded preservation reminder:
- Evidence-backed behavior that must remain correct:
- Highest-risk counterexample:
- Material unknown / uninspected surface:
- Known explicit anchors / upstream-downstream refs and disposition:
- Role-before-value ambiguity, if any:

Owner / retirement matrix:
- New canonical owner:
- Old owner:
- Compat-only carrier:
- Delete-first / retirement trigger:

Falsification matrix (evaluate in order; stop at the first failing gate):
- Gate 0 - Premise evidence (stage-graded): design stage accepts spec/logic
  refs; implementation/runtime stage requires log, telemetry, or test
  evidence. No evidence -> park as watch-listed, do not enter value
  evaluation.
- Gate 1 - Decidability: no obtainable evidence to judge it -> park as a
  watched falsifier, do not act.
- Gate 2 - Value (any one): lowers future fix probability / shrinks the
  solution set / exposes a missing actionable acceptance criterion / the same
  broken assumption is reused elsewhere. Passing here still requires
  gates 3-5.
- Gate 3 - Cost match: change cost vs business priority, costed at the
  current stage; a valid but deferred counterexample is recorded in the owner
  doc, never parked orally.
- Gate 4 - Goal regression: the constrained solution still meets the original
  goal; re-read the accepted-constraint list at existing checkpoints (design
  review, plan approval, pre-completion verification).
- Gate 5 - Minimize then classify: boundary-shaped destructive claims must be
  minimized first; premise attacks classify as destructive directly.
  Classes: destructive (refactor/retirement track) | supplementary (boundary
  constraint) | watch-listed (falsifier). Conflicting counterexamples are
  decided by business-goal ranking, never by stacking constraints.
- Gate 6 - Adoption trace: the cheapest checkable form (regression test for
  destructive; contract, assertion, or checklist line for supplementary),
  written into the existing owner doc.

Verdict:
- Adopt / revise / reject / needs evidence:
- Blocking