principle-subtract-before-you-add
Skill4 starsChanged 16 days agoMITView on GitHub
Use when planning the order of an addition, refactor, or rewrite. Clear out dead code and redundancy before building, so the system ends up simpler and no less capable, with a surface the same size or smaller.
47 other projects use a version of this.
Adopted by
Most recently taken up by
- paramcodes/skillstheir own version, first seen Nov 8, 2026
- tristanphvn/keeltheir own version, first seen Nov 8, 2026
- hidenobunagai/astacktheir own version, first seen Nov 8, 2026
- creedants/pstack-t3their own version, first seen Nov 3, 2026
- painhardcore/pstacktheir own version, first seen Nov 2, 2026
- silacode/agent-skillstheir own version, first seen Nov 1, 2026
Used with
Projects with it also use setup-pstack, poteto-help and 3 more.
Other files people use alongside this one.
Files found in the same public projects as a version of this one, more often than they turn up anywhere else. Each project counts once, large collections count for less, and this file's own repository is left out.
bnemaSkillsetup-pstack
Configure which Pi models pstack uses per role. Detects available provider/model specs and writes pstack's user configuration. Use for /setup-pstack, "configure pstack models", or changing pstack model choices.
Also in 25 projects that use this
ianclearySkillpoteto-help
Guides users through pstack setup, /poteto-mode, and picking the skill, playbook, or principle for a task. Type /poteto-help with a question.
Also in 14 projects that use this
tristanphvnSkillketchup-video
Catch the user up like /keel:ketchup, with a short silent video of slides for what happened and the waiting calls as text under it. Use for /keel:ketchup-video.
Also in 10 projects that use this
JoshueOsunaSkillPoteto Mode
poteto's agent style for concise, detailed responses, deliberate subagents, unslopped prose, simple code, and verified work. Use for poteto, /poteto-mode, or requests to work in this style.
Also in 3 projects that use this
instructureSkillketchup
Rebuild context after /clear by analyzing uncommitted changes across Canvas LMS and all plugin repositories
Also in 17 projects that use this
Other versions47 projects use a version of this.
Word for word · 0
None found.
Edited · 0
None found.
Wrote their own version · 47
- backnotprop/pstack★ 3.8ksame name
- jtaroreh/agystack★ 128same name
- uzairansaruzi/p3-stack★ 126same name
- dsebban/skills★ 71same name
- TheOnlyFusionCube/potetos-for-everyone★ 21same name
- creedants/pstack-t3★ 18same name
- painhardcore/pstack★ 18same name
- Scino/fstack★ 18same name
- mariusflorescu/pstack-t3★ 13same name
- adjohn/pstack★ 9same name
37 more not listed
How matches are found. Word for word: the exact same text. Edited: shares passages with this file (“99% same” means 99% of its five-word phrases also appear here; 10% or more counts). Their own version: similar meaning, or, weakest, the same name. We can’t tell which project had it first. Projects are counted among the 200 most-starred candidates, and mentions are links to the repository we found, up to 50 per site, so both counts are a floor.
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The file
We split this skill into the rules it gives an agent
2 rules. 0 are common, 2 are distinctive, and 0 are very specific to this project.
0
Common
Most of the 47 edited versions we read keep these.
2
Distinctive
This author's own choices. Worth a look.
0
Very specific
Tied to their project's names, files or tools. Probably skip.
- Common
- Distinctive
- Very specific
- Distinctive: line 20
Write only the validators, parsers, and guards that the spec and the real trust boundaries call for.
- Distinctive: line 22
When a doc, file, or link target adds nothing new, delete it.
“Common” is measured: kept by at least 6 in 10 of the 47 edited versions of this file we could read. “Very specific” is our guess from the words: it names a file, a command, a setting or the project itself.
Files
Subtract before you add
As a system changes, take complexity out before you put new code in. Make simplifying a habit, so every change leaves a design that is simpler, does at least as much, and exposes no more surface than before.
When it applies
Sequencing any addition, refactor, or rewrite. Subtraction is the default.
What to do
- Schedule removal work before construction work, and land it in its own commit.
- Cut to the minimum before polishing.
- Design for observed usage, not hypothetical edge cases.
- Write only the validators, parsers, and guards that the spec and the real trust boundaries call for. Validation at a genuine boundary is required (principle-boundary-discipline); a third copy of it deeper in is not.
- Apply the same rule to prompts and agent instructions: delete redundant instructions and oversized templates.
- When a doc, file, or link target adds nothing new, delete it. Do not leave a stub.
Subtraction shrinks attack surface. Before adding a new admin endpoint, remove the two unused debug endpoints beside it. Dead routes, unused dependencies, and orphaned feature flags are code that still runs, or still ships, with nobody watching it.
The failure it prevents
Building on dead weight, speculative defensive code, and stub files that mislead readers.
Done when
Dead code and redundancy are gone before new code lands.
Related: principle-foundational-thinking, principle-laziness-protocol, principle-sequence-verifiable-units.
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