principle-experience-first

principle-experience-first is a skill for Claude Code, OpenCode from painhardcore/pstack. It costs 37 tokens per session (260 once invoked), scanned A, a copy of principle-experience-first, MIT.

A set of product and user-experience guidelines for making decisions about features and implementation. It puts the needs of people using and maintaining the product ahead of engineering convenience.

In plain words
What is it for?
Use it when choosing feature scope, designing a user flow, deciding whether to prototype, or weighing product quality against implementation effort.
Why use it?
It helps teams avoid crowded, rough products and focus effort on a smaller number of well-finished features. It also draws attention to details such as feedback, errors, spacing, and transitions.

Skill for Claude CodeOpenCode

Written for Claude Code and OpenCode: shipped in a Claude Code plugin, but also installed under .opencode/.

Part of the pstack plugin — 41 skills, 2 agents shipped together

Good fit Use it when choosing feature scope, designing a user flow, deciding whether to prototype, or weighing product quality against implementation effort.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/painhardcore/pstack/principle-experience-first
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 painhardcore/pstack --skill principle-experience-first
Clone the repo
git clone --depth 1 https://github.com/painhardcore/pstack

Made for: Claude Code, OpenCode.

Or install pstack, the plugin that ships this one along with the rest of its 41 skills, 2 agents.

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 principle-experience-first

README.md
[![agentmods](https://agentmods.dev/badge/skills/painhardcore/pstack/principle-experience-first/github.svg)](https://agentmods.dev/skills/painhardcore/pstack/principle-experience-first)
Your own site
<a href="https://agentmods.dev/skills/painhardcore/pstack/principle-experience-first"><img src="https://agentmods.dev/badge/skills/painhardcore/pstack/principle-experience-first/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 principle-experience-first

Your own site · 80×15
<a href="https://agentmods.dev/skills/painhardcore/pstack/principle-experience-first"><img src="https://agentmods.dev/badge/skills/painhardcore/pstack/principle-experience-first.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 37 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 260 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 89% copy Near-identical to another mod 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 $0.00037 $0.00260
Opus 5.5 $0.00015 $0.00104
Sonnet 5.5 $0.00007 $0.00052
Haiku 4.5 $0.00004 $0.00026

Measured 1mo ago against content hash f8f61e0b0c21, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

principle-experience-first 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 1mo 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.

Origin

This is a copy

89% identical to principle-experience-first — 11 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

.opencode/skills/principle-experience-first/SKILL.md · 19 lines

What it actually says

Experience First

The product is the experience. Every technical decision either helps or hurts it. When implementation convenience conflicts with user delight, choose delight.

  • Say no to 1,000 things (every feature, control, and option must earn its place)
  • Ship less, ship better (polished experience with three features beats rough one with ten)
  • Prototype before committing (design decisions are cheaper in throwaway HTML than production code)
  • Sweat the details (transitions, alignment, spacing, feedback, error states)
  • Tighten the core loop (every feature should serve the central workflow or get out of the way)

The user is whoever consumes the work. For a UI that is the end user. For a library or an internal API it is the colleague who imports it. The engineer who maintains the code next is a user too. Weigh their experience the same way, and explain impact from their seat.

Foundations should serve the experience, not the other way around. Foundational thinking governs the sequence of work; this principle governs the target.

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. 1mo ago First seen · 19 lines · 37 tokens per session scan A f8f61e0b0c21

Subscribe to this mod's changes

principle-experience-first is a skill published in the GitHub repository painhardcore/pstack (12 stars, last pushed 5d ago), licensed MIT. It adds 37 tokens to every session and 260 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 89% identical to principle-experience-first, differing in 11 lines, and is treated as a copy.

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