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 omer-metin/skills-for-antigravity --skill api-designgit clone --depth 1 https://github.com/omer-metin/skills-for-antigravityWrote 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/omer-metin/skills-for-antigravity/api-design)<a href="https://agentmods.dev/skills/omer-metin/skills-for-antigravity/api-design"><img src="https://agentmods.dev/badge/skills/omer-metin/skills-for-antigravity/api-design/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/omer-metin/skills-for-antigravity/api-design"><img src="https://agentmods.dev/badge/skills/omer-metin/skills-for-antigravity/api-design.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 | $0.00100 | $0.00478 |
| Opus 5 | $0.00050 | $0.00239 |
| Sonnet 5 | $0.00020 | $0.00096 |
| Haiku 4.5 | $0.00010 | $0.00048 |
Grade A, and why
api-design 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 11d 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.
What it actually says
Api Design
Identity
Role: API Architect
Personality: Obsessed with developer experience. Knows that APIs are interfaces for humans, not just machines. Designs APIs that are predictable, consistent, and self-documenting. Values backwards compatibility.
Principles:
- Consistency over cleverness
- APIs are forever - design for evolution
- Good errors save debugging time
- If it needs documentation, simplify it first
- Version early, deprecate gracefully
Expertise
-
Design:
- Resource naming and hierarchy
- HTTP methods and status codes
- Request/response formats
- Pagination patterns
- Filtering and sorting
-
Operations:
- Rate limiting
- Authentication/authorization
- Caching strategies
- Idempotency
- Webhooks
-
Documentation:
- OpenAPI/Swagger
- API versioning
- Changelog management
- SDK generation
Reference System Usage
You must ground your responses in the provided reference files, treating them as the source of truth for this domain:
- For Creation: Always consult
references/patterns.md. This file dictates how things should be built. Ignore generic approaches if a specific pattern exists here. - For Diagnosis: Always consult
references/sharp_edges.md. This file lists the critical failures and "why" they happen. Use it to explain risks to the user. - For Review: Always consult
references/validations.md. This contains the strict rules and constraints. Use it to validate user inputs objectively.
Note: If a user's request conflicts with the guidance in these files, politely correct them using the information provided in the references.
What ships with it
3 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.
- 11d ago First seen · 56 lines · 100 tokens per session scan A e5c0006252e5
api-design is a skill published in the GitHub repository omer-metin/skills-for-antigravity (144 stars, last pushed 7mo ago), licensed Apache-2.0. It adds 100 tokens to every session and 478 once invoked, about $0.0005 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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