syn-json-validate

syn-json-validate is a skill for Claude Code, Codex from legendtkl/agentic-skill-router. It costs 29 tokens per session (133 once invoked), scanned A, original, MIT.

A skill for checking JSON documents against a JSON Schema, which defines the fields and data types they are expected to contain.

In plain words
What is it for?
Use it to validate JSON documents and report each rule violation.
Why use it?
It finds documents that do not match the required structure and identifies what is wrong.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to validate JSON documents and report each rule violation.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/legendtkl/agentic-skill-router/syn-json-validate
Install

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.

Any agent
npx skills add legendtkl/agentic-skill-router --skill syn-json-validate
Clone the repo
git clone --depth 1 https://github.com/legendtkl/agentic-skill-router

Made for: Claude Code, Codex.

Wrote 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.

agentmods badge for syn-json-validate

README.md
[![agentmods](https://agentmods.dev/badge/skills/legendtkl/agentic-skill-router/syn-json-validate/github.svg)](https://agentmods.dev/skills/legendtkl/agentic-skill-router/syn-json-validate)
Your own site
<a href="https://agentmods.dev/skills/legendtkl/agentic-skill-router/syn-json-validate"><img src="https://agentmods.dev/badge/skills/legendtkl/agentic-skill-router/syn-json-validate/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.

agentmods 80×15 button for syn-json-validate

Your own site · 80×15
<a href="https://agentmods.dev/skills/legendtkl/agentic-skill-router/syn-json-validate"><img src="https://agentmods.dev/badge/skills/legendtkl/agentic-skill-router/syn-json-validate.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 29 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 133 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00029 $0.00133
Opus 5 $0.00015 $0.00067
Sonnet 5 $0.00006 $0.00027
Haiku 4.5 $0.00003 $0.00013

Measured 9d ago against content hash 0d6eb3d1b569, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

syn-json-validate 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 9d 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.

experiments/dci-compare/synthetic-skills/syn-json-validate/SKILL.md · 23 lines

What it actually says

JSON data: JSON Schema validation

When to use

Use this skill for JSON Schema validation in JSON data. This skill specifically handles JSON Schema validation and nothing else in the JSON data family.

Procedure

Validate JSON documents against a JSON Schema and report each violation.

Notes

This is the JSON data skill dedicated to JSON Schema validation. Sibling skills cover other JSON data capabilities; this one is the right choice only when the task is about JSON Schema validation.

Changes

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.

  1. 9d ago First seen · 23 lines · 29 tokens per session scan A 0d6eb3d1b569

Subscribe to this mod's changes

syn-json-validate is a skill published in the GitHub repository legendtkl/agentic-skill-router (5 stars, last pushed 3mo ago), licensed MIT. It adds 29 tokens to every session and 133 once invoked, about $0.0001 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 2026-09-03.