additive-bias-defense

> The default answer to "should we add this?" is no.

> The burden of proof is on the addition.

Additive Bias Defense

> Note (#444): Frontmatter declares `provides.guidance`, not

> `provides.contract`. The scrutiny questions are consumed by

> partner skills (`pensive:code-refinement, conserve:unbloat`,

> `imbue:scope-guard`) that voluntarily embed them; no validator or

> hook in leyline enforces them directly. If a future contributor

> adds enforcement, restore the `contract` label and link the

> validator path here.

When NOT To Use

• Removing bloat that already landed (use conserve:bloat-detector)
• Scoring whether a feature is worth building (use imbue:scope-guard)

The Problem

LLMs are additive by nature. They reinvent wheels, add

unnecessary complexity, hallucinate issues and modify

tests to justify them, and deviate from priorities. This

contract provides a systemic defense.

The Scrutiny Questions

Applied to every proposed addition (code, files,

abstractions, error handling, configuration):

1. Priority alignment: Is this a deviation from the

current priority?

1. Criticality: Is it critical to implement at this

juncture?

1. Simplicity: Does a simpler or more elegant

solution exist?

1. Evidence: What evidence proves this is needed

(not assumed)?

1. Consequence: What breaks if we do not add this?

If the proposer cannot answer questions 4 and 5 with

concrete evidence, the addition is unjustified.

Anti-Pattern Detection

| Pattern | Signal | Challenge |

|---------|--------|-----------|

| Wheel reinvention | New utility/helper overlapping existing code | "Does X already do this?" |

| Hallucinated issues | Fix for a bug with no reproduction evidence | "Show the failing test before the fix" |

| Test manipulation | Test changed to match behavior rather than spec | "Did the spec change, or did you change the test?" |

| Complexity creep | Abstraction introduced for single use case | "Is this the 3rd use, or the 1st?" |

| Priority deviation | Work not traceable to current task/spec | "Which requirement does this serve?" |

| Gold plating | Error handling or flexibility beyond need | "What breaks without this?" |

Burden of Proof Verdict

After applying scrutiny questions and anti-pattern

detection, produce a verdict:

| Verdict | Meaning | Action |

|---------|---------|--------|

| justified | Evidence supports the addition | Proceed |

| needs_evidence | Plausible but unproven | Provide evidence or remove |

| unjustified | No evidence, likely bias | Remove or justify |

Integration Contract

Review-oriented skills MUST consult this contract by:

1. Applying the 5 scrutiny questions to each addition
2. Scanning for the 6 anti-patterns
3. Producing a burden-of-proof verdict
4. Including the verdict in their output

Consuming Skills

| Skill | Integration Point |

|-------|-------------------|

| attune:war-room | Prosecution Counsel role uses scrutiny questions |

| sanctum:pr-review | Every added file/function challenged |

| pensive:code-refinement | Refactors pass "3rd use" test |

| conserve:unbloat | Findings feed removal candidates |

| attune:mission-orchestrator | Plan sections scanned before user review |

| imbue:justify | Scrutiny questions extend audit protocol |

Related Skills

• imbue:karpathy-principles - "Simplicity First" and "Surgical Changes" principles invoke this contract from a higher-level four-principle synthesis
• See docs/quality-gates.md#skill-level-quality-gate-composition for the full gate-skill federation graph

The Subtraction Principle

> Rely less on AI and initial lines of thinking.

> Challenge yourself to think of a more elegant

> implementation or a simpler solution.

Before accepting any addition, ask: "Could I achieve

this by removing code instead of adding it?" If yes,

prefer the subtractive approach.

Exit Criteria

• [ ] All 5 scrutiny questions applied to every proposed addition;

questions 4 (evidence) and 5 (consequence) answered with

concrete evidence, not assumptions

• [ ] All 6 anti-patterns scanned (wheel reinvention, hallucinated

issues, test manipulation, complexity creep, priority deviation,

gold plating); any match named with the pattern label

• [ ] A burden-of-proof verdict produced for each addition:

justified, needs_evidence, or unjustified; the verdict

appears in the consuming skill's output

• [ ] Subtraction principle applied: at least one check for

"could this be achieved by removing code instead?" before

accepting any net-positive line-count change