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 rampstackco/claude-skills --skill calculator-designgit clone --depth 1 https://github.com/rampstackco/claude-skillsWrote 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/rampstackco/claude-skills/calculator-design)<a href="https://agentmods.dev/skills/rampstackco/claude-skills/calculator-design"><img src="https://agentmods.dev/badge/skills/rampstackco/claude-skills/calculator-design/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/rampstackco/claude-skills/calculator-design"><img src="https://agentmods.dev/badge/skills/rampstackco/claude-skills/calculator-design.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00145 | $0.04787 |
| Opus 5 | $0.00072 | $0.02393 |
| Sonnet 5 | $0.00029 | $0.00957 |
| Haiku 4.5 | $0.00015 | $0.00479 |
Grade A, and why
calculator-design 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 9d 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.
How it starts
The opening of the file, as written. The whole thing — 303 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Calculator Design
A senior growth practitioner's playbook for designing interactive calculators that deliver real decision-support value while serving as lead magnets and qualified-traffic generators. ROI calculators, pricing estimators, savings projections, mortgage calculators, custom assessments. The discipline of building a tool the audience actually trusts.
Most calculators on the web are bait. Random multipliers behind official-looking math; an "Industry Average" number that does not cite a source; the result hidden behind a contact-sales form. The calculator captures emails because the format implies calculation; the leads are unqualified because the calculator did not actually help anyone decide anything.
The calculators that work as compounding assets do something different. They give the audience a result they can defend to a stakeholder. They show the methodology so the result is interrogatable. They capture leads through value (a PDF report, a save-and-compare account, a custom analysis) rather than through manipulation.
This skill is one of the specific lead-magnet types covered as its own skill. The parent-frame methodology lives in lead-magnet-design; the calculator-specific methodology (calculation transparency, tiered value, methodology disclosure) lives here.
The voice is the senior growth practitioner who has watched calculators earn long-term credibility and watched them burn it within weeks of launch. Practical, opinionated about transparency, willing to say when a calculator is the wrong investment for the goal.
When to use this skill: scoping a calculator for the first time, auditing a calculator that converts but does not qualify, designing the methodology disclosure that earns audience trust, or deciding which features warrant the email gate.
What this skill covers
This skill spans calculator design as one specific lead-magnet type. The growth-tooling distinctions:
lead-magnet-designis the parent-frame methodology (when to invest in any magnet, format selection, audience-fit, follow-up sequence). Calculators are one specific lead-magnet type.calculator-design(this skill) is calculator-specific methodology (calculation transparency, tiered value, methodology disclosure, input design).quiz-and-assessment-designis a sister tool type. Calculators give numbers; quizzes give categories. The methodology differs.landing-page-copyis the calculator landing page (downstream of calculator design).pm-spec-writingis writing the spec for engineers building the calculator. This skill is about WHAT to build; pm-spec-writing is about communicating it.
What ships with it
9 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.
- references/calculation-logic-transparency.md 11 KB
- references/calculator-anti-patterns.md 10 KB
- references/calculator-investment-criteria.md 9.8 KB
- references/common-calculator-failures.md 9.1 KB
- references/email-capture-decision-tree.md 11 KB
- references/input-design-patterns.md 11 KB
- references/methodology-disclosure-templates.md 10 KB
- references/result-presentation-patterns.md 11 KB
- references/tiered-value-structures.md 10 KB
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.
- 9d ago First seen · 303 lines · 145 tokens per session scan A 8ed49b035454
calculator-design is a skill published in the GitHub repository rampstackco/claude-skills (830 stars, last pushed yesterday), licensed MIT. It adds 145 tokens to every session and 4,787 once invoked, about $0.0007 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.
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