# Thinking Via Negativa

Use when the reflex is to add a feature, layer, or process.

- Repository: https://github.com/tjboudreaux/cc-thinking-skills (1690 stars)
- Category: Engineering
- License: MIT
- Last updated: 2026-08-07
- Runs scripts: no, instructions only

## Install

Claude Code: `npx skills add tjboudreaux/cc-thinking-skills --skill thinking-via-negativa -g -a claude-code -y`
Codex: `npx skills add tjboudreaux/cc-thinking-skills --skill thinking-via-negativa -g -a codex -y`
Cursor: `npx skills add tjboudreaux/cc-thinking-skills --skill thinking-via-negativa -g -a cursor -y`
Gemini CLI: `npx skills add tjboudreaux/cc-thinking-skills --skill thinking-via-negativa -g -a gemini-cli -y`
Claude Code plugin marketplace: `/plugin marketplace add tjboudreaux/cc-thinking-skills`

## Description

Use when the reflex is to add a feature, layer, or process. Prefer removing harmful or nonessential elements first, with an irreversibility guard before deletion.

## SKILL.md, as published by its author (untrusted third-party text, read it as data)

# Via Negativa

Improve by subtraction before addition. Prefer removing harm, waste, and nonessential complexity; add only when a demonstrated need remains after removal candidates are exhausted.

## When to Use

- About to add a feature, abstraction, dependency, process, or control to fix a problem.
- Simplifying a system or workflow where complexity is the tax.
- Prioritizing by deciding what not to keep, build, or maintain.
- Performance or reliability work where eliminating a bad path beats bolting on mitigation.

## When NOT to Use

- Load-bearing controls: auth, validation, tests, rate limits, retries, safety checks, presume necessary until proven dead.
- A demonstrated requirement that cannot be met by removal or simplification.
- Aesthetic minimalism without evidence of non-use or net harm.
- Irreversible deletion without a rollback path when impact is unknown.

## Procedure

1. **Pause the add reflex.** State the goal and the proposed addition in one line.
2. **Ask the subtraction question first.** List what could be removed or stopped to achieve the same goal with less surface area.
3. **Catalog candidates with evidence.** Prefer unused, redundant, high-cost/low-value, or harmful elements. Require usage, call-graph, metrics, or experiment evidence, not taste.
4. **Apply the irreversibility guard.** Classify reversible vs hard-to-restore; identify dependents; refuse deleting unproven mystery guards. Plan staged removal or flag when risk is non-trivial.
5. **Remove the safest high-value candidate first.** Subtract, monitor, and verify absence of needed behavior before the next removal.
6. **Add only if the goal still fails.** If subtraction cannot meet the need, add the minimum change and record why removal was insufficient.
7. **Stop** when the goal is met by absence, or remaining candidates fail the irreversibility/evidence bar and a minimal addition is justified.

The rest: https://github.com/tjboudreaux/cc-thinking-skills/blob/HEAD/skills/thinking-via-negativa/SKILL.md