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 thapaliyabikendra/ai-artifacts --skill api-design-principlesgit clone --depth 1 https://github.com/thapaliyabikendra/ai-artifactsWrote 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/thapaliyabikendra/ai-artifacts/api-design-principles)<a href="https://agentmods.dev/skills/thapaliyabikendra/ai-artifacts/api-design-principles"><img src="https://agentmods.dev/badge/skills/thapaliyabikendra/ai-artifacts/api-design-principles.svg" alt="Measured on agentmods" 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 | $0.00038 | $0.02377 |
| Opus 5 | $0.00019 | $0.01189 |
| Sonnet 5 | $0.00008 | $0.00475 |
| Haiku 4.5 | $0.00004 | $0.00238 |
Grade A, and why
api-design-principles 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 8d 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 — 319 lines — stays where its author put it; the contents beside it link to each section on GitHub.
API Design Principles
Master REST API design principles to build intuitive, scalable, and maintainable APIs. This skill focuses on design theory - for implementation patterns, see abp-api-implementation or abp-service-patterns.
When to Use This Skill
- Designing new REST API contracts
- Reviewing API specifications before implementation
- Establishing API design standards for your team
- Planning API versioning and evolution strategy
- Creating developer-friendly API documentation
Audience
- Backend Architects - API contract design
- Tech Leads - Standards and review
- Business Analysts - Understanding API capabilities
For Implementation: Use
abp-service-patternsfor AppService code,api-response-patternsfor response wrappers,fluentvalidation-patternsfor validation.
Core Principles
1. Resource-Oriented Design
APIs expose resources (nouns), not actions (verbs).
| Concept | Good | Bad |
|---|---|---|
| Resource naming | /patients, /appointments |
/getPatients, /createAppointment |
| Actions via HTTP methods | POST /patients |
POST /createPatient |
| Plural for collections | /patients |
/patient |
| Consistent casing | kebab-case or camelCase |
Mixed styles |
Resource Hierarchy:
/api/v1/patients # Collection
/api/v1/patients/{id} # Single resource
/api/v1/patients/{id}/appointments # Nested collection
/api/v1/appointments/{id} # Direct access to nested resource
Avoid Deep Nesting (max 2 levels):
# Good - Shallow
GET /api/v1/patients/{id}/appointments
GET /api/v1/appointments/{id}
# Bad - Too deep
GET /api/v1/clinics/{id}/doctors/{id}/patients/{id}/appointments/{id}
2. HTTP Methods Semantics
| Method | Purpose | Idempotent | Safe | Request Body |
|---|---|---|---|---|
GET |
Retrieve resource(s) | Yes | Yes | No |
POST |
Create resource | No | No | Yes |
PUT |
Replace entire resource | Yes | No | Yes |
PATCH |
Partial update | Yes* | No | Yes |
DELETE |
Remove resource | Yes | No | No |
What ships with it
2 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.
- 8d ago First seen · 319 lines · 38 tokens per session scan A d8eb2c545254
api-design-principles is a skill published in the GitHub repository thapaliyabikendra/ai-artifacts (24 stars, last pushed 5mo ago), licensed Apache-2.0. It adds 38 tokens to every session and 2,377 once invoked, about $0.0002 per session on Opus 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 2026-08-30.
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