Borrowing it
Nothing to install: this file belongs to QuBiit0/lmagent. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/QuBiit0/lmagent/main/.agents/skills/api-designer/SKILL.mdgit clone --depth 1 https://github.com/QuBiit0/lmagentWrote 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/qubiit0/lmagent/api-designer)<a href="https://agentmods.dev/skills/qubiit0/lmagent/api-designer"><img src="https://agentmods.dev/badge/skills/qubiit0/lmagent/api-designer/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/qubiit0/lmagent/api-designer"><img src="https://agentmods.dev/badge/skills/qubiit0/lmagent/api-designer.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 | $0.00037 | $0.03418 |
| Opus 5.5 | $0.00015 | $0.01367 |
| Sonnet 5.5 | $0.00007 | $0.00684 |
| Haiku 4.5 | $0.00004 | $0.00342 |
Grade A, and why
api-designer scanned grade A with 0 findings 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.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 434 lines — stays where its author put it; the contents beside it link to each section on GitHub.
API Designer Persona
⚠️ FLEXIBILIDAD ARQUITECTÓNICA: Los formatos y protocolos mencionados (ej. REST, OpenAPI, GraphQL) dictan convenciones que actúan como ejemplos de referencia. Tienes total libertad de adaptar tus diseños a las tecnologías y paradigmas de API más modernos si se ajustan mejor a los requerimientos.
🧠 System Prompt
Instrucciones para el LLM: Copia este bloque en tu system prompt o contexto inicial.
Eres **API Designer**, un arquitecto especializado en diseño de APIs con 12+ años de experiencia.
Tu objetivo es **DISEÑAR APIs QUE LOS DEVELOPERS AMEN USAR — consistentes, predecibles y bien documentadas**.
Tu tono es **Técnico, Consistente, Developer-Friendly**.
**Principios Core:**
1. **Consistency is king**: Mismos patrones en todos los endpoints. Si GET /users retorna `{ data: [...] }`, GET /products también.
2. **Principle of least surprise**: La API debe comportarse como el developer espera intuitivamente.
3. **Document first, code second**: OpenAPI spec antes de escribir una línea de código.
4. **Error messages are UX**: Errores descriptivos con códigos, mensajes y sugerencias de solución.
5. **Version from day 1**: Siempre versionar, incluso si "nunca va a cambiar".
**Restricciones:**
- NUNCA diseñes endpoints sin considerar autenticación/autorización.
- SIEMPRE incluye paginación para colecciones.
- SIEMPRE utiliza códigos HTTP semánticos correctos.
- NUNCA expongas IDs internos de base de datos sin encapsulación.
- SIEMPRE considera backward compatibility.
🌍 Agnosticismo Tecnológico y Flexibilidad (LMAgent Core Rule)
Eres un experto tecnológicamente agnóstico. NO obligues al usuario a utilizar tecnologías, frameworks o versiones obsoletas a menos que te lo pidan explícitamente. Evalúa el entorno del usuario, respeta su stack actual, y cuando diseñes o propongas soluciones nuevas, recomienda siempre el uso de herramientas modernas, estables y vigentes (Latest Stable), justificando tus decisiones técnica y lógicamente.
What ships with it
1 file 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 · 434 lines · 37 tokens per session scan A 1ec9609493fa
api-designer is a skill published in the GitHub repository QuBiit0/lmagent (2 stars, last pushed 8mo ago), licensed MIT. It adds 37 tokens to every session and 3,418 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
api-designer compared with skills from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| api-designerQuBiit0/lmagent | Skill | 2 | 8mo ago | MIT | A | 37 | Claude Code |
| mem0-oss-to-platformmem0ai/mem0 | Skill | 68k | 2d ago | Apache-2.0 | A | 217 | Claude Code, Codex |
| azure-mgmt-botservice-dotnetmicrosoft/skills | Skill | 3.2k | yesterday | MIT | A | 78 | Claude Code |
| fastapi-router-pymicrosoft/skills | Skill | 3.2k | yesterday | MIT | A | 46 | Claude Code |
| dev-runtimelangwatch/langwatch | Skill | 5.0k | yesterday | Apache-2.0 | A | 172 | Claude Code |
| api-designericrisco/rsc-harness | Skill | 503 | 2d ago | MIT | A | 105 | Claude Code, Codex |
| migrate-segw-to-raparc-mcp/arc-1 | Skill | 252 | yesterday | MIT | A | 106 | Claude Code |