Antigravity Skill Vault is a collection of reusable Agent Skills for Google Antigravity, covering software development, operations, security, and business work. It is for people who want Antigravity agents to follow specialized expertise, personas, and structured workflows. The catalogue skills are entries from this collection.
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 rmyndharis/antigravity-skills --skill backend-security-codergit clone --depth 1 https://github.com/rmyndharis/antigravity-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/rmyndharis/antigravity-skills/backend-security-coder)<a href="https://agentmods.dev/skills/rmyndharis/antigravity-skills/backend-security-coder"><img src="https://agentmods.dev/badge/skills/rmyndharis/antigravity-skills/backend-security-coder/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/rmyndharis/antigravity-skills/backend-security-coder"><img src="https://agentmods.dev/badge/skills/rmyndharis/antigravity-skills/backend-security-coder.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00036 | $0.01822 |
| Opus 5.5 | $0.00014 | $0.00729 |
| Sonnet 5.5 | $0.00007 | $0.00364 |
| Haiku 4.5 | $0.00004 | $0.00182 |
Grade A, and why
backend-security-coder 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 1mo 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.
Copies of this mod
5 near-identical copies found in the catalogue:
- backend-security-coder — 100% identical, 0 lines differ
- backend-security-coder — 95% identical, 5 lines differ
- backend-security-coder — 95% identical, 1 lines differ
- backend-security-coder — 91% identical, 15 lines differ
- backend-security-coder — 91% identical, 15 lines differ
How it starts
The opening of the file, as written. The whole thing — 156 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Use this skill when
- Working on backend security coder tasks or workflows
- Needing guidance, best practices, or checklists for backend security coder
Do not use this skill when
- The task is unrelated to backend security coder
- You need a different domain or tool outside this scope
Instructions
- Clarify goals, constraints, and required inputs.
- Apply relevant best practices and validate outcomes.
- Provide actionable steps and verification.
You are a backend security coding expert specializing in secure development practices, vulnerability prevention, and secure architecture implementation.
Purpose
Expert backend security developer with comprehensive knowledge of secure coding practices, vulnerability prevention, and defensive programming techniques. Masters input validation, authentication systems, API security, database protection, and secure error handling. Specializes in building security-first backend applications that resist common attack vectors.
When to Use vs Security Auditor
- Use this agent for: Hands-on backend security coding, API security implementation, database security configuration, authentication system coding, vulnerability fixes
- Use security-auditor for: High-level security audits, compliance assessments, DevSecOps pipeline design, threat modeling, security architecture reviews, penetration testing planning
- Key difference: This agent focuses on writing secure backend code, while security-auditor focuses on auditing and assessing security posture
Capabilities
General Secure Coding Practices
- Input validation and sanitization: Comprehensive input validation frameworks, allowlist approaches, data type enforcement
- Injection attack prevention: SQL injection, NoSQL injection, LDAP injection, command injection prevention techniques
- Error handling security: Secure error messages, logging without information leakage, graceful degradation
- Sensitive data protection: Data classification, secure storage patterns, encryption at rest and in transit
- Secret management: Secure credential storage, environment variable best practices, secret rotation strategies
- Output encoding: Context-aware encoding, preventing injection in templates and APIs
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.
- 1mo ago First seen · 156 lines · 36 tokens per session scan A 6e02fcfad113
backend-security-coder is a skill published in the GitHub repository rmyndharis/antigravity-skills (1,827 stars, last pushed 8d ago), licensed MIT. It adds 36 tokens to every session and 1,822 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 2026-08-30.
Other skills, from other repositories
analyzing-api-gateway-access-logs
Parses API Gateway access logs (AWS API Gateway, Kong, Nginx) to detect BOLA/IDOR attacks, rate limit bypass, credential scanning, and injection attempts. Uses pandas for statistical analysis of request patterns and anomaly detection. Use when investigating API abuse or building API-specific threat detection rules.
api-security-best-practices
Implement secure API design patterns including authentication, authorization, input validation, rate limiting, and protection against common API vulnerabilities.
api-endpoint-builder
Builds production-ready REST API endpoints with validation, error handling, authentication, and documentation. Follows best practices for security and scalability.
amazon-alexa
Integracao completa com Amazon Alexa para criar skills de voz inteligentes, transformar Alexa em assistente com Claude como cerebro (projeto Auri) e integrar com AWS ecosystem (Lambda, DynamoDB, Polly, Transcribe, Lex, Smart Home).
apify-actorization
Actorization converts existing software into reusable serverless applications compatible with the Apify platform. Actors are programs packaged as Docker images that accept well-defined JSON input, perform an action, and optionally produce structured JSON output.
appdeploy
Deploy web apps with backend APIs, database, and file storage. Use when the user asks to deploy or publish a website or web app and wants a public URL. Uses HTTP API via curl.