Zod Skill

Zod Skill

Created by Anivar Aravind

An AI agent skill for writing, validating, and debugging Zod v4 schemas with modern best practices.

The Problem

AI agents often generate outdated Zod v3 patterns — z.string().email() instead of z.email(), z.nativeEnum() instead of z.enum(), required_error instead of the error parameter — and miss critical parsing pitfalls like using parse() instead of safeParse(), forgetting parseAsync for async refinements, or assuming z.object() preserves unknown keys. These produce schemas that compile but silently misbehave at runtime.

This Solution

27 rules with incorrect→correct code examples that teach agents Zod v4's actual API behavior, schema design patterns, error handling, architectural placement, observability, and TypeScript integration. Each rule targets a specific mistake and shows exactly how to fix it.

Install

npx skills add anivar/zod-skill -g

Or with full URL:

npx skills add https://github.com/anivar/zod-skill

Baseline

• zod ^4.0.0
• TypeScript ^5.5

What's Inside

27 Rules Across 9 Categories

| Priority | Category | Rules | Impact | |----------|----------|-------|--------| | 1 | Parsing & Type Safety | 3 | CRITICAL | | 2 | Schema Design | 4 | CRITICAL | | 3 | Refinements & Transforms | 3 | HIGH | | 4 | Error Handling | 3 | HIGH | | 5 | Performance & Composition | 3 | MEDIUM | | 6 | v4 Migration | 3 | MEDIUM | | 7 | Advanced Patterns | 3 | MEDIUM | | 8 | Architecture & Boundaries | 3 | CRITICAL/HIGH | | 9 | Observability | 2 | HIGH/MEDIUM |

Each rule file contains:

• Why it matters
• Incorrect code with explanation
• Correct code with explanation
• Decision tables and additional context

9 Deep-Dive References

| Reference | Covers | |-----------|--------| | schema-types.md | All primitives, string formats, numbers, enums, dates, files, JSON | | parsing-and-inference.md | parse, safeParse, parseAsync, z.infer, z.input, coercion | | objects-and-composition.md | object/strict/loose, pick, omit, partial, recursive, unions, tuples | | refinements-and-transforms.md | refine, superRefine, transform, pipe, defaults, catch | | error-handling.md | ZodError, flattenError, treeifyError, error customization, i18n | | advanced-features.md | Codecs, branded types, JSON Schema, registries, Standard Schema | | anti-patterns.md | 14 common mistakes with BAD/GOOD examples | | boundary-architecture.md | Where Zod fits: Express, tRPC, Next.js, React Hook Form, env, external APIs | | linter-and-ci.md | ESLint rules, CI schema snapshots, unused schema detection, circular deps |

Structure

├── SKILL.md                          # Entry point for AI agents
├── AGENTS.md                         # Compiled guide with all rules expanded
├── rules/                            # Individual rules (Incorrect→Correct)
│   ├── parse-*                       # Parsing & type safety (CRITICAL)
│   ├── schema-*                      # Schema design (CRITICAL)
│   ├── refine-*                      # Refinements & transforms (HIGH)
│   ├── error-*                       # Error handling (HIGH)
│   ├── perf-*                        # Performance & composition (MEDIUM)
│   ├── migrate-*                     # v4 migration (MEDIUM)
│   ├── pattern-*                     # Advanced patterns (MEDIUM)
│   ├── arch-*                        # Architecture & boundaries (CRITICAL/HIGH)
│   └── observe-*                     # Observability (HIGH/MEDIUM)
└── references/                       # Deep-dive reference docs
    ├── schema-types.md
    ├── parsing-and-inference.md
    ├── objects-and-composition.md
    ├── refinements-and-transforms.md
    ├── error-handling.md
    ├── advanced-features.md
    ├── anti-patterns.md
    ├── boundary-architecture.md
    └── linter-and-ci.md

Ecosystem — Skills by Anivar Aravind

Testing Skills

| Skill | What it covers | Install | |-------|---------------|---------| | jest-skill | Jest best practices — mock design, async testing, matchers, timers, snapshots | npx skills add anivar/jest-skill -g | | zod-testing | Zod schema testing — safeParse, mock data, property-based | npx skills add anivar/zod-testing -g | | msw-skill | MSW 2.0 API mocking — handlers, responses, GraphQL | npx skills add anivar/msw-skill -g | | redux-saga-testing | Redux-Saga testing — expectSaga, testSaga, providers | npx skills add anivar/redux-saga-testing -g |

Library & Framework Skills

| Skill | What it covers | Install | |-------|---------------|---------| | redux-saga-skill | Redux-Saga effects, fork model, channels, RTK | npx skills add anivar/redux-saga-skill -g | | msw-skill | MSW 2.0 handlers, responses, migration | npx skills add anivar/msw-skill -g |

Engineering Analysis

| Skill | What it covers | Install | |-------|---------------|---------| | contributor-codebase-analyzer | Code analysis, annual reviews, promotion readiness | npx skills add anivar/contributor-codebase-analyzer -g |

Author

Anivar Aravind — Building AI agent skills for modern JavaScript/TypeScript development.

License

MIT

Source & license

This open-source MCP server is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: anivar
• Source: anivar/zod-skill
• License: MIT
• Homepage: https://skills.sh/anivar/zod-skill

Install and usage instructions live in the source repository linked above.