design-an-interface
by mattpocockThe design-an-interface skill helps you explore radically different API and module interface shapes before you commit. It is built for frontend development and other module-design work where you want requirements first, then multiple options, trade-off comparison, and a cleaner caller-facing contract.
This skill scores 67/100, which means it is listable but best framed as a moderately useful, specialized workflow rather than a highly polished install. Directory users get a real, triggerable process for interface design with enough structure to reduce guesswork, but they should expect some limits because the skill has no supporting scripts/resources and the repository only contains the SKILL.md workflow.
- Clear triggerability: the description explicitly says to use it when designing an API, exploring interface options, comparing module shapes, or when asked to "design it twice".
- Concrete operational workflow: it instructs the agent to gather requirements, spawn 3+ parallel sub-agents, and compare radically different designs with a defined output template.
- Good install decision value for a niche task: the body is substantial, has multiple headings and constraints, and gives agents a repeatable method rather than a generic brainstorming prompt.
- No supporting assets, scripts, or references: adoption depends entirely on the SKILL.md text, so there is little extra executable guidance beyond the document itself.
- It is in a deprecated path, which may signal lower maintenance or reduced long-term reliability even though the workflow content itself is usable.
Overview of design-an-interface skill
The design-an-interface skill helps you avoid locking into the first API shape that comes to mind. It is built for frontend development and other module-design work where you need multiple interface options, not a single polished draft. If you are deciding how a component, helper, service, or module should be called, this skill pushes the model to generate radically different designs and compare them before you commit.
The real job-to-be-done is interface selection under uncertainty: clarify callers, surface constraints, and compare trade-offs across a few distinct shapes. That is especially useful when you know the behavior you want but not the cleanest surface area, or when you need a design that fits existing patterns without exposing internal complexity.
What makes design-an-interface different
Unlike a generic prompt that asks for “an API design,” the design-an-interface skill is opinionated about process: gather requirements first, then create several parallel options, then evaluate them against the use case. That structure is valuable when the cost of a bad interface is high, such as refactoring churn, poor composability, or awkward usage in frontend code.
Best-fit use cases
Use design-an-interface when you need to:
- shape a new module or component API
- compare a minimal interface with a more flexible one
- decide what should be hidden versus exposed
- translate a vague product need into a concrete developer-facing contract
- explore interface options before coding a shared frontend utility
When it is less useful
This skill is not for polishing an already-settled interface or for generating visual UI mockups. If the contract is already fixed, a normal prompt is usually enough. The design-an-interface skill is strongest when uncertainty is still high and you want disciplined option generation, not just a single answer.
How to Use design-an-interface skill
Install and load it in your workflow
For design-an-interface install, add the skill from the repository path in your skills setup and then open the skill instructions before asking for output. Start with SKILL.md; in this repo snapshot, that is the only file, so there is no broader rule set to reconcile. The absence of supporting files means the prompt needs to carry more project-specific context than a larger skill pack would.
Give the skill the right input shape
The best design-an-interface usage begins with a short problem brief, not a request like “design an interface.” Include:
- what the module does
- who calls it
- the top 2–4 operations
- constraints such as performance, compatibility, or existing conventions
- what must stay internal
Strong input looks like this:
- “Design an interface for a cache layer used by React data hooks. Callers need get/set/invalidate, keys are strings, eviction must stay internal.”
- “Design an interface for a form state helper in a frontend app. Optimize for common cases, but keep async validation pluggable.”
Weak input looks like:
- “Make me an API”
- “Design this module better”
Follow the workflow, not just the output
The skill works best when you preserve its sequence:
- gather requirements
- spawn 3+ parallel designs
- compare trade-offs before choosing
If you skip the requirement pass, the generated interfaces tend to optimize for the wrong thing. If you skip comparison, you lose the main value of the design-an-interface guide: finding a better boundary, not just a prettier signature.
Practical repo-reading path
Because this repository is lightweight, the main source of truth is SKILL.md. Read the workflow section carefully and use it to write your prompt. If you are adapting it for your own frontend development repo, keep the same structure but replace the example constraints with your own domain rules and caller expectations.
design-an-interface skill FAQ
Is design-an-interface only for frontend development?
No, but design-an-interface for Frontend Development is a strong fit because frontend code often needs narrow, ergonomic APIs that stay stable across components and hooks. It also works for services, libraries, and internal tooling where interface shape matters.
How is this different from asking an AI to “design an API”?
A generic prompt usually produces one solution. The design-an-interface skill is designed to force option diversity and comparison, which is the part most people skip. That makes it better when the right answer depends on trade-offs rather than on one obvious pattern.
Do beginners need to know architecture to use it?
No. Beginners can use it if they can describe the problem, the callers, and a few constraints. The skill is actually helpful for beginners because it turns vague design thinking into a repeatable process instead of relying on intuition alone.
When should I not use this skill?
Do not use it for final copyediting, UI styling, or changes where the interface is already established and you only need implementation details. It is also a poor fit when you cannot describe the module’s callers or constraints, because the design options will be too generic.
How to Improve design-an-interface skill
Provide constraints that change the design
The biggest quality boost comes from constraints that force real trade-offs. Say whether you want fewer methods, more flexibility, backward compatibility, or a pattern aligned with existing frontend code. The design-an-interface skill produces much better results when each sub-agent has a different goal.
Ask for distinct design strategies
If you want useful output, request variation explicitly: minimal surface, highly extensible surface, common-case optimized surface, or pattern-inspired surface. That makes the design-an-interface usage more actionable because the comparison reveals which interface matches your product reality, not just which one sounds elegant.
Share caller examples and failure cases
The skill improves when you include concrete call sites, awkward edge cases, and things the interface must hide. For frontend work, mention whether the caller is a React component, hook, service, or test harness. That context helps the model choose signatures that feel natural in the codebase rather than abstractly “clean.”
Iterate by choosing, then tightening
After the first pass, do not ask for “more ideas” without a reason. Pick the most promising design, then ask for a second round focused on the weakest trade-off: fewer methods, better naming, simpler call sites, or stronger encapsulation. That is the fastest way to make design-an-interface useful beyond initial exploration.