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Trellis: Skill for Claude Code

.agents/skills/first-principles-thinking/SKILL.md

first-principles-thinking is a skill for Claude Code, Codex from mindfold-ai/Trellis. It costs 164 tokens per session (4,001 once invoked), scanned A, original, AGPL-3.0.

A structured way to examine a problem from its basic assumptions upward. It encourages questioning why a design exists and whether a different approach would be better.

In plain words
What is it for?
Use it when analyzing a design, challenging an approach, or asking whether there is a better solution.
Why use it?
It helps uncover hidden assumptions and avoid accepting an existing design without checking its foundations.

Skill for Claude CodeCodex

Which agent this was written for is unclear — body not stored (licence); the path alone says nothing. Also seen: installed under .agents/ (shared by several agents).

This is mindfold-ai/Trellis's own configuration. It tells Claude Code and Codex how to work on Trellis itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything Trellis configures →

not rated 15krepo +29 1mo ago A scan SkillSpector: pass 164 tokens AGPL-3.0
View source ↗ mindfold-ai/Trellis docs.trytrellis.app
About the project

Trellis is an engineering framework that stores project specifications, tasks, and working memory in a repository so coding agents can follow consistent development practices across sessions. Teams use it to organize AI-assisted planning, implementation, review, and validation across multiple coding platforms. The catalogue entries provide Trellis commands, agents, hooks, skills, instructions, and settings.

mindfold-ai/Trellis · 15,098 stars · on GitHub · docs.trytrellis.app

Reuse

Borrowing it

Nothing to install: this file belongs to mindfold-ai/Trellis. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/mindfold-ai/Trellis/main/.agents/skills/first-principles-thinking/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/mindfold-ai/Trellis

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for first-principles-thinking

README.md
[![agentmods](https://agentmods.dev/badge/skills/mindfold-ai/trellis/first-principles-thinking/github.svg)](https://agentmods.dev/skills/mindfold-ai/trellis/first-principles-thinking)
Your own site
<a href="https://agentmods.dev/skills/mindfold-ai/trellis/first-principles-thinking"><img src="https://agentmods.dev/badge/skills/mindfold-ai/trellis/first-principles-thinking/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for first-principles-thinking

Your own site · 80×15
<a href="https://agentmods.dev/skills/mindfold-ai/trellis/first-principles-thinking"><img src="https://agentmods.dev/badge/skills/mindfold-ai/trellis/first-principles-thinking.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 164 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,001 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
Origin unknown No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00164 $0.04001
Opus 5.5 $0.00066 $0.01600
Sonnet 5.5 $0.00033 $0.00800
Haiku 4.5 $0.00016 $0.00400

Measured 2mo ago against content hash bcf5f2092684, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

first-principles-thinking scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2mo ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.agents/skills/first-principles-thinking/SKILL.md · 404 lines

The source is not reproduced here

Licensed AGPL-3.0

The repository is licensed AGPL-3.0, which this catalogue does not treat as permission to reproduce the file. Read it at the source.

Read it on GitHub

Files

What ships with it

5 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2mo ago First seen · 404 lines · 164 tokens per session scan A bcf5f2092684

Subscribe to this mod's changes

first-principles-thinking is a skill published in the GitHub repository mindfold-ai/Trellis (15,098 stars, last pushed 1mo ago), licensed AGPL-3.0. It adds 164 tokens to every session and 4,001 once invoked, about $0.0007 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

Planningagentic-codingai-workflowclaudecodecodexharness
Related

first-principles-thinking compared with skills from other repositories

first-principles-thinking next to 6 skills from other repositories
ModTypeStarsLast pushLicenceScanTokensWorks with
first-principles-thinkingmindfold-ai/TrellisSkill15k1mo agoAGPL-3.0A164Claude Code, Codex
ospec-goalclawplays/ospecSkill3902mo agoMITA29Codex
ospecclawplays/ospecSkill3902mo agoMITA26Claude Code, Codex
ospec-changeclawplays/ospecSkill3902mo agoMITA18Codex
dotcraft-unityDotHarness/dotcraft-unitySkill2411d agoApache-2.0A64Codex
unityDotHarness/dotcraft-unitySkill2411d agoApache-2.0A32Codex
standup-updategszr/lunarSkill18yesterdayMITA49Claude Code, Codex