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.
npx skills add sergekostenchuk/ui-ux-agent-skill-system --skill tech-stack-selectorgit clone --depth 1 https://github.com/sergekostenchuk/ui-ux-agent-skill-systemWrote 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.
[](https://agentmods.dev/skills/sergekostenchuk/ui-ux-agent-skill-system/tech-stack-selector)<a href="https://agentmods.dev/skills/sergekostenchuk/ui-ux-agent-skill-system/tech-stack-selector"><img src="https://agentmods.dev/badge/skills/sergekostenchuk/ui-ux-agent-skill-system/tech-stack-selector/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.
<a href="https://agentmods.dev/skills/sergekostenchuk/ui-ux-agent-skill-system/tech-stack-selector"><img src="https://agentmods.dev/badge/skills/sergekostenchuk/ui-ux-agent-skill-system/tech-stack-selector.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00069 | $0.00473 |
| Opus 5.5 | $0.00028 | $0.00189 |
| Sonnet 5.5 | $0.00014 | $0.00095 |
| Haiku 4.5 | $0.00007 | $0.00047 |
Grade A, and why
tech-stack-selector 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.
What it actually says
Tech Stack Selector
This skill decides the implementation stack for UI/UX projects. It is advisory until a build task is created; it does not deploy or mutate infrastructure.
Operating Modes
select: choose a stack for a new site or app after concept.review: evaluate an existing stack against SEO, UX, editing, maintainability, and deployment needs.migration: recommend whether to keep, improve, or replace the current stack.
Required Workflow
- Read references/stack-decision-framework.md.
- Gather product type, editing needs, content volatility, SEO/LLM requirements, interaction complexity, hosting constraints, and team skills.
- Score viable options: static HTML, Vite/React, Next.js, Astro, CMS-backed, custom admin, or existing stack.
- Recommend one stack, one fallback, and disqualified options with reasons.
- Hand off to
marketing-site-skill,webapp-ui-skill,pencil-design-bridge, or infra/launch skills as appropriate.
Safety Rules
- Do not provision servers, buy domains, change DNS, or deploy production from this skill.
- Do not claim current package versions or vendor pricing without verifying if the user needs exact current facts.
- Prefer the simplest stack that satisfies SEO, content editing, performance, and maintainability.
Output Shape
Recommended stack:
Fallback stack:
Disqualified options:
Why this fits:
SEO/LLM implications:
Editing/admin implications:
Deployment implications:
Risks:
Next skill:
Validation
python3 $CODEX_HOME/skills/.system/skill-creator/scripts/quick_validate.py $CODEX_HOME/skills/tech-stack-selector
python3 $CODEX_HOME/skills/senior-skill-architect/scripts/lint_production_skill.py $CODEX_HOME/skills/tech-stack-selector
What ships with it
3 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.
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.
- 1mo ago First seen · 50 lines · 69 tokens per session scan A 4195abc34dc4
tech-stack-selector is a skill published in the GitHub repository sergekostenchuk/ui-ux-agent-skill-system (32 stars, last pushed 1mo ago), licensed Apache-2.0. It adds 69 tokens to every session and 473 once invoked, about $0.0003 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.
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