Create a custom tool to simplify a step in your work
Turn a recurring calculation, template, or comparison into a tool with inputs, a result, and a test.
Let's understand the idea
If you keep repeating the same calculation, text formatting, or size selection, you can build a tool for yourself instead of manually requesting the result each time. Write down the inputs, rules, and output, and prepare examples with known answers. Start with one function.
Distinguish between a fixed calculation and a feature that calls an AI model each time. The first can run on clear rules. The second needs a service, a budget, and key protection appropriate to the environment. Do not present a demo button as connected to a real service. Test the limits and any saving features.
Tools for this workflow
Choose from what's available to you. You can use these prompts with several tools. What they can carry out depends on supported features and files.
See tool details and uses in the Tools library →Examples to expand the idea
A salesperson calculates his commission manually each month: a percentage for each product and a bonus if he exceeds his target. He describes the method to Gemini Canvas, which builds a calculator where he enters sales and gets his commission. He tests it on two months he calculated manually before relying on it.
Compare offers
Specify the items, units, and rules, and show missing information instead of automatically declaring a winner.
Prompt template generator
Fields, examples, previewing, editing, and copying the final text, with missing information kept visible.
Review before publishing
A checklist for your work to review text, dimensions, and links, not an automatic certificate that the content is correct.
Steps from start to delivery
Open any step by its heading. Each explains what to do, why, and what to check before continuing.
1Choose a recurring stepOne useful function.Details
A small, clearly defined tool is easier to test than a large platform.
What should I do?
- Write down what you do manually, its inputs, and its output.
- Define what is enough for a first version.
2Write the rules and examplesRules and examples to check the tool against.Details
Testing a calculation requires an expected result.
What should I do?
- Prepare normal examples, boundary cases, and missing values.
- Specify the units, rounding, and expected output.
3Define behavior and savingStated behavior and clear limits.Details
Saving on your device is different from saving in a shared account.
What should I do?
- Explain what happens with empty inputs, errors, and resetting.
- Specify whether you need saving, exporting, or an external service.
4Build and test the casesOutput that matches your known examples.Details
Attractive buttons need to produce correct results.
What should I do?
- Ask for an actual version using the simplest suitable approach.
- Test the examples, limits, copying or exporting, and mobile use.
Tools for this part: choose one5Use it on a new taskA useful tool with limits you can explain.Details
Testing on the same example is not enough.
What should I do?
- Try a new input and calculate it manually.
- Save a copy and the date of the rules, and indicate if any part is still experimental.
Prompts for your work
Open a prompt and fill in your details. Empty fields remain visible so you don't forget them.
Turn the step into a toolOpen it to copy or tailor the prompt
Prepare the listed inputs and start with the prompt in an available tool. Open the output and review it against your work.
Copy the prompt as it is, or tailor it with your details first.
Tailor the prompt to your workOptional: add your details and the prompt adjusts itself
View full prompt
Why is the prompt written this way?
Clarifying behavior and inputs helps us build something people can use, beyond just a page's appearance.
Test the tool and its limitsOpen it to copy or tailor the prompt
Copy the prompt as it is, or tailor it with your details first.
Tailor the prompt to your workOptional: add your details and the prompt adjusts itself
View full prompt
Did the result serve your original goal?
Return to the inputs and sources, and open the output where you'll use it. Check these points before relying on it.
- Are the rules and units known?
- Have the cases and limits been tested?
- Are saving, the service, and cost clear?
If there's a problem, name the unsuitable part, show an example, and request a specific edit.