API Designer
Jeffallan/claude-skills
Designs REST and GraphQL APIs from resource modeling to an OpenAPI 3.1 contract, with versioning, pagination and RFC 7807 error handling.
Interface design principles for package APIs — where configuration, behavior, and state belong across schema, endpoint, and hook layers.
Install Interface Design
$ npx skills add reactive/data-client --skill interface-design -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install reactive/data-client interface-design --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/reactive/data-client.git skills-src && mkdir -p .claude/skills && cp -r skills-src/.agents/skills/interface-design .claude/skills/interface-design && rm -rf skills-srcUse ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.
Claude Code skills documentation · loads skills from .claude/skills/
Install the "interface-design" agent skill from https://github.com/reactive/data-client/tree/master/.agents/skills/interface-design into .claude/skills/interface-design/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "interface-design", then confirm the skill loads.Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$skill-installer install https://github.com/reactive/data-client/tree/master/.agents/skills/interface-designType this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
$ npx skills add reactive/data-client --skill interface-design -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install reactive/data-client interface-design --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/reactive/data-client.git skills-src && mkdir -p .agents/skills && cp -r skills-src/.agents/skills/interface-design .agents/skills/interface-design && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "interface-design" agent skill from https://github.com/reactive/data-client/tree/master/.agents/skills/interface-design into .agents/skills/interface-design/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "interface-design", then confirm the skill loads.Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add reactive/data-client --skill interface-design -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install reactive/data-client interface-design --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/reactive/data-client.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/.agents/skills/interface-design .cursor/skills/interface-design && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "interface-design" agent skill from https://github.com/reactive/data-client/tree/master/.agents/skills/interface-design into .cursor/skills/interface-design/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "interface-design", then confirm the skill loads.Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gemini skills install https://github.com/reactive/data-client.git --path .agents/skills/interface-design--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add reactive/data-client --skill interface-design -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install reactive/data-client interface-design --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/reactive/data-client.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/.agents/skills/interface-design .gemini/skills/interface-design && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "interface-design" agent skill from https://github.com/reactive/data-client/tree/master/.agents/skills/interface-design into .gemini/skills/interface-design/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "interface-design", then confirm the skill loads.Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gh skill install reactive/data-client interface-designInstalls for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
$ npx skills add reactive/data-client --skill interface-design -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/reactive/data-client.git skills-src && mkdir -p .github/skills && cp -r skills-src/.agents/skills/interface-design .github/skills/interface-design && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "interface-design" agent skill from https://github.com/reactive/data-client/tree/master/.agents/skills/interface-design into .github/skills/interface-design/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "interface-design", then confirm the skill loads.GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add reactive/data-client --skill interface-design -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install reactive/data-client interface-design --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/reactive/data-client.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/.agents/skills/interface-design .opencode/skills/interface-design && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "interface-design" agent skill from https://github.com/reactive/data-client/tree/master/.agents/skills/interface-design into .opencode/skills/interface-design/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "interface-design", then confirm the skill loads.OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
Facts
- Skill name
interface-design- GitHub stars
- 2k
- Token cost
- ~1.1k tokens
- SKILL.md length
- 487 words
- Files
- 1
- Skills in repo
- 17
- Repo updated
- First seen
- Licence
- Apache-2.0
At a glance
Interface design principles for package APIs — where configuration, behavior, and state belong across schema, endpoint, and hook layers.
- Changing options
- SKILL.md covers The Three Layers, Placement Principles, Declarative Over Imperative and What Stays the Same vs. What…, plus 1 more section
- Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
- State in packages/
What it does
Interface Design is an agent skill from reactive/data-client. Interface design principles for package APIs — where configuration, behavior, and state belong across schema, endpoint, and hook layers. Use when adding or changing options, behavior, or state in packages/.
Its SKILL.md is about 1.1k tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.
It sits in Backend & APIs, covering API design. The repository describes itself as: Async State Management without the Management. REST, GraphQL, SSE, Websockets. The licence is Apache-2.0.
When your agent uses it
- Changing options
- State in packages/
Example prompts
- “/interface-design”
What it can do on your machine
Read from SKILL.md and the folder at commit 02c0932. It shows what the files ask for, not the result of running them.
Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
No scripts in the folder and no shell commands in SKILL.md.
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.
Context cost
Interface Design loads about 1.1k tokens when it runs. Until then it costs about 56 tokens; SKILL.md has 487 words of instructions outside code blocks.
Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.
Safety
Auto-check passed
The automated check found no risky patterns in SKILL.md.
Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.
SKILL.md
The full file from reactive/data-client at commit 02c0932, republished under its Apache-2.0 licence (© reactive). 487 words, ~1,062 tokens.
Download SKILL.mdSave it as
.claude/skills/interface-design/SKILL.md (or your agent's skills folder).- name
- interface-design
- description
- Interface design principles for package APIs — where configuration, behavior, and state belong across schema, endpoint, and hook layers. Use when adding or changing options, behavior, or state in packages/*.
Interface Design
Resources are a collection of methods for a given data model. Entities and Schemas declaratively define the data model. Endpoints are the methods on that data. Both should be as declarative as possible — describing what, not how.
These concerns separate into three layers. Each changes for different reasons, is used in different contexts, and composes independently. Place new configuration or behavior in the layer whose reason to change matches.
The Three Layers
| Layer | Declares… | Changes when… | Examples |
|---|---|---|---|
| Schema (Entity, Collection, Query) | Data model and relationships | Data shape or identity changes | pk(), schema, merge(), process(), indexes |
| Endpoint (Endpoint, RestEndpoint, resource) | Methods on that data | API contract or cache policy changes | path, method, schema, pollFrequency, getOptimisticResponse() |
| Hook / Composable (useSuspense, useDLE, useQuery) | Data dependencies at point of use | UI interaction pattern changes | Suspense, { data, loading, error }, subscription lifecycle |
Placement Principles
If it describes data identity or relationships → Schema. Schemas are protocol-agnostic and UI-agnostic. An Entity's pk(), merge(), and nested schema work identically whether data arrives via REST, WebSocket, or controller.set().
If it describes how to obtain or mutate data → Endpoint. Declare path, method, schema, and policy — not imperative fetch logic. Endpoints are UI-agnostic: the same endpoint powers React, Vue, SSR, or imperative controller.fetch().
If it describes how the user experiences data → Hook. Loading states, error delivery, suspense, subscriptions, and reactivity adapters are UI concerns. Hooks co-locate data dependencies where data is rendered — not at the top of a tree. They are thin adapters over Controller, not duplicate cache logic.
If it's shared policy (expiry, staleness, optimistic updates) → EndpointExtraOptions. These live on endpoints as per-request policy, but are implemented by Controller/managers, not hooks.
Show full SKILL.md (216 more words)Show less
Declarative Over Imperative
Favor declarative configuration that the framework interprets over imperative code users must write:
- Schemas: Declare
pk(),schemarelationships,merge()policy — the store handles normalization. - Endpoints: Declare
path,method,schema,optimistic— the framework handles fetching, caching, and updates. - Mutations:
ctrl.fetch(TodoResource.partialUpdate, { id }, { completed })— a single typed statement describing the action, not manual cache updates or invalidation cascades.
What Stays the Same vs. What Varies
The endpoint + args input pattern is the stable interface shared by all hooks and controller.fetch. This enables one endpoint definition to power useSuspense, useDLE, useCache, useSubscription, or imperative controller.fetch — without the endpoint knowing which UI pattern consumes it.
When adding a new capability, ask:
- Does every consumer need this? → Endpoint or schema.
- Do only some UI patterns need this? → Hook or hook option.
- Does it vary per call site? → An argument, not a property.
- Does it vary per endpoint definition? → A property or
extend()override.
Anti-patterns
- Imperative update/invalidation logic where a declarative schema or
optimisticflag suffices - Encoding UI concerns (loading, error display) into endpoint or schema definitions
- Encoding transport details (URL construction, headers) into hooks or components
- Duplicating store/cache logic in hooks instead of going through
Controller - Adding hook-specific state to
Controller— it serves all consumers (React, Vue, imperative) - Prop-drilling fetched data instead of co-locating
useSuspensewhere data is rendered
© reactive, Apache-2.0. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file
Files
Just SKILL.md in .agents/skills/interface-design of reactive/data-client.
Open the folder on GitHubat commit 02c0932
Compare with similar skills
Interface Design next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| Interface Design this skillreactive/data-client | 2k | — | ~1.1k | Automated safety check: Pass | Apache-2.0 | |
| API DesignerJeffallan/claude-skills | 12k | 2 repos | ~2k | Automated safety check: Pass | MIT | |
| Nodejs Backend Patternsever-works/ever-works | 158 | 17 repos | ~4k | Automated safety check: Pass | AGPL-3.0 | |
| Pangolin CRUD Endpointsfosrl/pangolin | 23k | — | ~461 | Automated safety check: Pass | Custom licence | |
| Backend PatternshellangleZ/burn-in-cceverywhere-ralph | 112 | 17 repos | ~3.3k | Automated safety check: Pass | None | |
| API And Interface Designdzhalaevd/Donatello | 135 | 9 repos | ~2.6k | Automated safety check: Pass | Apache-2.0 |
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Related
Categories
Questions about Interface Design
What does Interface Design do?
Interface design principles for package APIs — where configuration, behavior, and state belong across schema, endpoint, and hook layers. Interface Design is an agent skill from reactive/data-client. Interface design principles for package APIs — where configuration, behavior, and state belong across schema, endpoint, and hook layers.
When should I use Interface Design?
Interface Design fits situations like: changing options; state in packages/.
How do I install Interface Design in Claude Code?
Run `npx skills add reactive/data-client --skill interface-design -a claude-code`. Or copy the skill folder (.agents/skills/interface-design in reactive/data-client) into .claude/skills/interface-design in your project. Claude Code loads it when a task matches its description.
How do I install Interface Design in Codex?
Run `npx skills add reactive/data-client --skill interface-design -a codex`. Or copy the skill folder (.agents/skills/interface-design in reactive/data-client) into .agents/skills/interface-design in your project. Codex loads it when a task matches its description.
Can I use Interface Design in Cursor, Gemini CLI or GitHub Copilot?
Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add reactive/data-client --skill interface-design -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/interface-design, .gemini/skills/interface-design, .github/skills/interface-design and .opencode/skills/interface-design in your project.
What does Interface Design need to run?
SKILL.md names no scripts, command-line tools or credentials: Interface Design is instructions for the agent only.
Does Interface Design access the network?
SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.
Is Interface Design safe to install?
Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.
What licence does Interface Design use?
Interface Design is published under the Apache-2.0 licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.
How many tokens does Interface Design use?
About 1.1k tokens (SKILL.md is roughly 4.2k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.
What are the alternatives to Interface Design?
Skills that share tags, products or a category with Interface Design: API Designer (Jeffallan/claude-skills, 12k stars), Nodejs Backend Patterns (ever-works/ever-works, 158 stars), Pangolin CRUD Endpoints (fosrl/pangolin, 23k stars) and Backend Patterns (hellangleZ/burn-in-cceverywhere-ralph, 112 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Interface Design?
reactive (a GitHub organization) maintains it in reactive/data-client, which has 2,037 GitHub stars. The repository holds 17 skills in this directory. The repository was last updated on October 7, 2026.
Source: reactive/data-client on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.