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 paraskakis/skills --skill design-apigit clone --depth 1 https://github.com/paraskakis/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/paraskakis/skills/design-api)<a href="https://agentmods.dev/skills/paraskakis/skills/design-api"><img src="https://agentmods.dev/badge/skills/paraskakis/skills/design-api/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/paraskakis/skills/design-api"><img src="https://agentmods.dev/badge/skills/paraskakis/skills/design-api.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00090 | $0.04568 |
| Opus 5.5 | $0.00036 | $0.01827 |
| Sonnet 5.5 | $0.00018 | $0.00914 |
| Haiku 4.5 | $0.00009 | $0.00457 |
Grade A, and why
design-api scanned grade A with 1 finding 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 2mo 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.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
- **curl + python3** — used for the RMOA API call. Almost always pre-installed. Copies of this mod
1 near-identical copy found in the catalogue:
- design-api — 89% identical, 41 lines differ
How it starts
The opening of the file, as written. The whole thing — 370 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Design API
Design an API end-to-end: requirements → stories → OpenAPI spec → lint → iterate. This is Emmanuel Paraskakis's method for designing APIs with LLMs.
All four foundation files (requirements, domain, standards, OpenAPI best practices) are always required. Stories are optional — if provided, they represent the human's design decisions and the skill skips straight to spec generation. If not, the skill generates stories first and pauses for review.
Scope and Routing
Triggering is defined in the frontmatter description. In scope: the complete requirements-to-linted-spec pipeline. Out of scope: when the user wants only one artifact — route to the single skill (design-api-stories, design-api-spec, or design-api-review) instead.
Execute the phases inline. The phases below summarize the sibling skills (design-api-stories, design-api-spec). Do NOT re-invoke those skills as separate skill calls — this skill's own input gathering replaces theirs. If the sibling SKILL.md files are installed, consult them for detail when a phase summary is not enough; otherwise the content here is sufficient to execute.
Optional Dependencies
The core skill (stories + spec generation) works with no extra tools. For the full experience:
- RateMyOpenAPI API key — enables automated linting and scoring. Free signup at api.ratemyopenapi.com/docs. Set as
RMOA_API_KEYenv var. - Node.js — enables local Swagger UI preview via
npx http-server. - curl + python3 — used for the RMOA API call. Almost always pre-installed.
Without these, the skill still generates a complete OpenAPI spec — it just skips linting and local preview.
Inputs
The user must provide (or point to) these files. Files can be named anything — identify each file by its # Title heading or content, not by filename.
Always required:
- Requirements — ICP, needs, pain points, use cases, benefits. The "why" and "what." Look for a heading like
# Requirements,# Research, or similar. - Domain — Data objects, properties, enums, object relations. Source of truth for schemas. Look for a heading like
# Domain,# Domain Model, or similar. - API Standards — Style guide, naming, paths, security, error handling. Source of truth for conventions. Look for a heading like
# API Standards,# Style Guide, or similar. - OpenAPI Best Practices — Formatting rules, DRY principles, SDK compatibility, component structure. Source of truth for OpenAPI document quality. Look for a heading like
# OpenAPI Best Practices,# OAS Best Practices, or similar.
What ships with it
4 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.
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.
- 2mo ago First seen · 370 lines · 90 tokens per session scan A c21e3e849c98
design-api is a skill published in the GitHub repository paraskakis/skills (43 stars, last pushed 17d ago), licensed MIT. It adds 90 tokens to every session and 4,568 once invoked, about $0.0004 per session on Opus 5.5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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