psych-decision-fundamentals

psych-decision-fundamentals is a skill for Claude Code from volomydyr/design-engineer-plugin. It costs 84 tokens per session (1,782 once invoked), scanned A, original, MIT.

A UX design guide about how people make choices, including loss aversion, decision fatigue, anchoring, and default options. It applies these ideas to interfaces with choices such as pricing, forms, and filters.

In plain words
What is it for?
Use it to review pricing pages, forms, filters, and other interfaces where people must compare or select options.
Why use it?
It helps identify designs that make decisions confusing or accidentally manipulative. The guidance emphasizes supporting clear choices without using dark patterns.

Skill for Claude Code

Written for Claude Code: disable-model-invocation in frontmatter. Also seen: model in frontmatter; names the AskUserQuestion tool.

Part of the design-engineer plugin — 57 skills, 11 commands, 10 agents, 6 hooks shipped together

Good fit Use it to review pricing pages, forms, filters, and other interfaces where people must compare or select options.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/volomydyr/design-engineer-plugin/psych-decision-fundamentals
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add volomydyr/design-engineer-plugin --skill psych-decision-fundamentals
Clone the repo
git clone --depth 1 https://github.com/volomydyr/design-engineer-plugin

Made for: Claude Code.

Or install design-engineer, the plugin that ships this one along with the rest of its 57 skills, 11 commands, 10 agents, 6 hooks.

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 psych-decision-fundamentals

README.md
[![agentmods](https://agentmods.dev/badge/skills/volomydyr/design-engineer-plugin/psych-decision-fundamentals/github.svg)](https://agentmods.dev/skills/volomydyr/design-engineer-plugin/psych-decision-fundamentals)
Your own site
<a href="https://agentmods.dev/skills/volomydyr/design-engineer-plugin/psych-decision-fundamentals"><img src="https://agentmods.dev/badge/skills/volomydyr/design-engineer-plugin/psych-decision-fundamentals/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 psych-decision-fundamentals

Your own site · 80×15
<a href="https://agentmods.dev/skills/volomydyr/design-engineer-plugin/psych-decision-fundamentals"><img src="https://agentmods.dev/badge/skills/volomydyr/design-engineer-plugin/psych-decision-fundamentals.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 84 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,782 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.
Origin original 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 $0.00084 $0.01782
Opus 5 $0.00042 $0.00891
Sonnet 5 $0.00017 $0.00356
Haiku 4.5 $0.00008 $0.00178

Measured 11d ago against content hash fe7d0d83b9b1, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

psych-decision-fundamentals 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 11d 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.

skills/psych-decision-fundamentals/SKILL.md · 153 lines

How it starts

The opening of the file, as written. The whole thing — 153 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Psychology of Decision-Making: Core Principles (Laws 21-25)

You are a psychology-informed design advisor specializing in how users make decisions. You help designers create interfaces that support clear, confident decision-making – through ethical influence, not manipulation.

Reference Files

  • section-3a-principles.md – all 5 principles with definitions, UX applications, good/bad examples, and merged cognitive bias content

Decision Hierarchy

  1. User's direct instructions – highest authority
  2. Project documentation – what has already been decided
  3. AI suggestions – lowest weight, always cite specific principles

Core Insight

Every design decision either helps or hinders user decision-making. Users arrive with limited cognitive resources, pre-existing beliefs, and a tendency to follow the path of least resistance. The five principles in this section explain why users decide the way they do and how to design interfaces that lead to better outcomes for both users and the business – without crossing into manipulation.

Ethical Boundary

Decision-making principles are high-risk for dark patterns. For every recommendation:

  • State whether the design serves the user's interest or only business metrics
  • Distinguish ethical influence (helping users make informed decisions) from manipulation (exploiting cognitive weaknesses)
  • Flag Loss Aversion and Anchoring Bias as highest-risk for manipulative application

Workflow

Step 1: Understand the Context

  1. Pricing / plan selection – I will focus on Anchoring Bias, Loss Aversion, and Default Bias
  2. Form design / checkout – I will focus on Decision Fatigue and Default Bias
  3. Search / filter / recommendations – I will focus on Confirmation Bias and Decision Fatigue
  4. Settings / preferences – I will focus on Default Bias and Decision Fatigue
  5. Full decision audit – I will review all 5 principles across your design
  6. Something else – describe your specific need

Read the full file on GitHub · 153 lines

Files

What ships with it

2 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. 11d ago First seen · 153 lines · 84 tokens per session scan A fe7d0d83b9b1

Subscribe to this mod's changes

psych-decision-fundamentals is a skill published in the GitHub repository volomydyr/design-engineer-plugin (20 stars, last pushed 2mo ago), licensed MIT. It adds 84 tokens to every session and 1,782 once invoked, about $0.0004 per session on Opus 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.

Related

Other skills, from other repositories

webgl-holographic-foil

A self-contained WebGL2 hero: thin-film interference over a crushed-foil surface whose palette shifts with the viewing angle; move the cursor to tilt the film.

nexu-io/open-design · 41 tokens

html-ppt-hermes-cyber-terminal

OpenDesign + BYOK: choosing and wiring your own model, hands-on — cost, quality, and the routing decision. Built as a decision-grade AI literacy deck for engineers, IT, applied-AI teams.

nexu-io/open-design · 53 tokens

html-ppt-taste-brutalist

16:9 HTML deck in tactical-telemetry / CRT-terminal taste. Deactivated-CRT charcoal slides, white-phosphor monospace, hazard-red accent, scanline overlay, ASCII syntax, density over decoration. Distilled from Leonxlnx/taste-skill brutalist-skill (Tactical Telemetry mode).

nexu-io/open-design · 78 tokens

visual-ralph

Visual Ralph orchestration for frontend UI from generated references, static references, or live URL targets, using $ralph with built-in visual verdict and pixel-diff evidence until the implementation matches and leaves a reproducible design system.

Yeachan-Heo/oh-my-codex · 50 tokens

accessibility

Consolidated accessibility skill entrypoint for WCAG 2.2, ARIA Authoring Practices, cognitive accessibility, Section 508, EN 301 549, design intent verification, and the Accessibility Planner workflow.

microsoft/hve-core · 47 tokens

make-resume

A Chinese-language tool for creating editable HTML resumes that can be changed in a browser and printed to PDF. It uses available resume templates when they are installed and otherwise provides a simpler fallback.

Hisn00w/ASu-skills · 86 tokens