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 agentmods add skills/rmyndharis/antigravity-skills/c4-codenpx skills add rmyndharis/antigravity-skills --skill c4-codegit 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/c4-code)<a href="https://agentmods.dev/skills/rmyndharis/antigravity-skills/c4-code"><img src="https://agentmods.dev/badge/skills/rmyndharis/antigravity-skills/c4-code.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 | $0.00054 | $0.01608 |
| Opus 5 | $0.00027 | $0.00804 |
| Sonnet 5 | $0.00011 | $0.00322 |
| Haiku 4.5 | $0.00005 | $0.00161 |
Grade A, and why
c4-code 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 5d 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
1 near-identical copy found in the catalogue:
- c4-code — 100% identical, 1 lines differ
How it starts
The opening of the file, as written. The whole thing — 244 lines — stays where its author put it; the contents beside it link to each section on GitHub.
C4 Code Level: [Directory Name]
Use this skill when
- Working on c4 code level: [directory name] tasks or workflows
- Needing guidance, best practices, or checklists for c4 code level: [directory name]
Do not use this skill when
- The task is unrelated to c4 code level: [directory name]
- 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.
Overview
- Name: [Descriptive name for this code directory]
- Description: [Short description of what this code does]
- Location: [Link to actual directory path]
- Language: [Primary programming language(s)]
- Purpose: [What this code accomplishes]
Code Elements
Functions/Methods
functionName(param1: Type, param2: Type): ReturnType- Description: [What this function does]
- Location: [file path:line number]
- Dependencies: [what this function depends on]
Classes/Modules
ClassName- Description: [What this class does]
- Location: [file path]
- Methods: [list of methods]
- Dependencies: [what this class depends on]
Dependencies
Internal Dependencies
- [List of internal code dependencies]
External Dependencies
- [List of external libraries, frameworks, services]
Relationships
Optional Mermaid diagrams for complex code structures. Choose the diagram type based on the programming paradigm. Code diagrams show the internal structure of a single component.
Object-Oriented Code (Classes, Interfaces)
Use classDiagram for OOP code with classes, interfaces, and inheritance:
---
title: Code Diagram for [Component Name]
---
classDiagram
namespace ComponentName {
class Class1 {
+attribute1 Type
+method1() ReturnType
}
class Class2 {
-privateAttr Type
+publicMethod() void
}
class Interface1 {
<<interface>>
+requiredMethod() ReturnType
}
}
Class1 ..|> Interface1 : implements
Class1 --> Class2 : uses
### Functional/Procedural Code (Modules, Functions)
For functional or procedural code, you have two options:
**Option A: Module Structure Diagram** - Use `classDiagram` to show modules and their exported functions:
```mermaid
---
title: Module Structure for [Component Name]
---
classDiagram
namespace DataProcessing {
class validators {
<<module>>
+validateInput(data) Result~Data, Error~
+validateSchema(schema, data) bool
+sanitize(input) string
}
class transformers {
<<module>>
+parseJSON(raw) Record
+normalize(data) NormalizedData
+aggregate(items) Summary
}
class io {
<<module>>
+readFile(path) string
+writeFile(path, content) void
}
}
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.
- 5d ago First seen · 244 lines · 54 tokens per session scan A 7dd1e22d5917
c4-code is a skill published in the GitHub repository rmyndharis/antigravity-skills (1,480 stars, last pushed 1mo ago), licensed MIT. It adds 54 tokens to every session and 1,608 once invoked, about $0.0003 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.
Other skills, from other repositories
idea-validator
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code-review
Systematic code review skill covering both requesting a review (pre-commit checklist) and receiving and responding to review feedback. Checks code quality, security, test coverage, architectural alignment, and documentation before any code is committed.
test-driven-execution
Before writing any implementation code, define the acceptance criteria and test cases that the code must satisfy. Agents then write code to pass these tests — not to match a vague description. Eliminates "it works on my machine" and "I think this is what you wanted" outcomes.
writing-plans
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changelog
Generates and maintains changelogs following Keep a Changelog format. Use when updating release notes, finishing tasks, or tagging versions. For version bumps, see semantic-versioning.