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?
2. Criticality: Is it critical to implement at this juncture?
3. Simplicity: Does a simpler or more elegant solution exist?
4. Evidence: What evidence proves this is needed (not assumed)?
5. 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

Burden of Proof Verdict

After applying scrutiny questions and anti-pattern detection, produce a verdict:

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

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