Use free-tools when considering calculators, analyzers, or interactive guides as a way to attract relevant readers. It is primarily an opportunity and scope-planning method. The existence of a tool category does not prove another version can gain traffic.
Install and invoke
Run this in your project terminal to install only this skill for Claude Code:
npx skills add coreyhaines31/marketingskills --skill free-tools -a claude-code
Node.js and npx must be available. For Codex, replace -a claude-code with -a codex. In the agent conversation, explicitly ask it to use free-tools and supply your material. The installation command belongs in the terminal, not in your content brief.
Describe a concrete task
Explain how people solve the problem today, where alternatives fall short, and why those users might also need your main product. A popular tool serving an unrelated audience may be a poor investment for your team.
Example brief:
Use free-tools to evaluate a meeting-cost calculator, image-dimension checker, and project-handoff assessment.
Our audience is small design studios. We have one development week and cannot support paid APIs or ongoing manual data entry.
Compare alternatives and meaningful differences, then choose one concept. Specify inputs, outputs, formulas or rules, scope, and stopping criteria.
Mark missing search data as unknown rather than forecasting traffic.
Ask the agent to explain demand, audience fit, differentiation, feasibility, and maintenance separately. A score helps organize judgment; it does not replace user evidence. The fact that another company charges for something does not establish that you can provide a reliable free version indefinitely.
Deliver one complete result
Define what users enter, what they receive, and how to interpret it. Calculators need explicit assumptions and formulas. Analyzers need a clear inspection scope, and generators need output limitations. Accounts and history may be unnecessary initially, but boundaries affecting correctness are essential.
Choose email capture based on the actual exchange. The tool can remain open or offer an optional detailed report after an initial result. Calling it a marketing tool does not require forced login. Explain operation, sample inputs, and limitations so a reader can finish the task without buying the main product.
Before implementation, list external APIs, data refresh work, input handling, and running costs. Continuous scraping or manual maintenance may conflict with a low-maintenance objective. After release, check correct task completion, repeated use, and relevant next actions before expanding. Traffic and usage are useful diagnostics, but neither alone establishes successful customer acquisition.
Validate one complete input-to-result path
Start with a small problem customers currently solve in a spreadsheet or by hand. Ask the skill to define the input, the calculation or decision rule, what the result helps the user decide, and when the result is unreliable. For a budget estimator, provide real pricing rules and publishable assumptions. If contracts vary widely, show a range and explain it rather than display a falsely precise total.
The first version should complete one path: open the page, enter realistic values, obtain a useful result, and understand the next step. Do not add accounts, a dashboard, and multiple report types at once. Request a one-page brief covering required fields, error messages, result explanation, data retention, and maintenance owner. Then observe three people from the target audience using it; watch for misunderstandings. A calculator, tester, generator, or library should be chosen by the job, not solely by which format appears easiest to rank.
Decide lead capture separately. A fully gated result may prevent visitors from judging whether the tool is worth using; optional saving or advice after the result may be more appropriate. Compare actual use, repeat visits, and relevant product inquiries, not form submissions alone. Include upkeep in the plan: who will notice when a rule, price, or external API changes and update the tool?
Example: set boundaries for a pricing estimator
Imagine a service business wants a free estimate calculator. Base price, user tiers, and implementation fees are known, but custom contracts cannot be represented by one public price. Give the skill the approved pricing rules and ask: “Use free-tools to design a first estimator. Define fields, formula, invalid inputs, result explanation, and cases that require a human quote. Produce a useful range, not a final contractual price. No account system in the first version.”
Check three hand-calculated examples: minimum usage, just over a tier boundary, and outside the public pricing range. The result should explain assumptions and excluded charges. Out-of-range inputs should lead to a quote request, not a falsely precise extrapolation. If the proposal needs five APIs, login, and a complex dashboard before showing a result, the first release is too large. Reduce it until a visitor can input values and understand the estimate within a minute.
Check the tool format against real search intent
Before building a calculator, search the target question and inspect whether leading results are functioning tools or explanatory articles. If users want an immediate calculation, let them enter data and get a credible result on the page instead of only showing “learn more.” Ahrefs described replacing a Website Traffic Checker landing page with a usable tool. That illustrates the value of delivering the result first, not a run of this Skill. After launch, track tool starts, completed results, and organic entrances separately.
An adjacent, inspectable case is DNSSpy’s DNS propagation checker. Its builder saw free search results with many ads and light features, then reused existing infrastructure to ship 40-plus resolvers, TTL, response time and DNSSEC with no signup. He did not report using this Skill or measuring paid conversion. The useful lesson is to put differentiation in the actual result and admit the free-tool-to-paid-trial attribution problem. At minimum, track input starts, completed results and visits to the relevant paid-product path.