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/vercel-labs/json-render/devtoolsnpx skills add vercel-labs/json-render --skill devtoolsgit clone --depth 1 https://github.com/vercel-labs/json-renderWhat 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 | $0.00108 | $0.02161 |
| Opus 5 | $0.00054 | $0.01081 |
| Sonnet 5 | $0.00022 | $0.00432 |
| Haiku 4.5 | $0.00011 | $0.00216 |
Grade A, and why
devtools 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 yesterday.
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.
How it starts
The opening of the file, as written. The whole thing — 186 lines — stays where its author put it; the contents beside it link to each section on GitHub.
@json-render/devtools
A floating inspector panel for json-render apps. Framework-agnostic core + per-framework adapters (React, Vue, Svelte, Solid).
Production-safe: the component renders null when NODE_ENV === "production".
Install
Install the core package plus the adapter that matches the host app's renderer.
# React
npm install @json-render/devtools @json-render/devtools-react
# Vue
npm install @json-render/devtools @json-render/devtools-vue
# Svelte
npm install @json-render/devtools @json-render/devtools-svelte
# Solid
npm install @json-render/devtools @json-render/devtools-solid
Drop-in usage
Place <JsonRenderDevtools /> anywhere inside the existing <JSONUIProvider> (or framework equivalent). No other wiring required.
React
import { JsonRenderDevtools } from "@json-render/devtools-react";
<JSONUIProvider registry={registry} handlers={handlers}>
<Renderer spec={spec} registry={registry} />
<JsonRenderDevtools spec={spec} catalog={catalog} messages={messages} />
</JSONUIProvider>;
Vue
<script setup>
import { JsonRenderDevtools } from "@json-render/devtools-vue";
</script>
<template>
<JSONUIProvider :registry="registry">
<Renderer :spec="spec" :registry="registry" />
<JsonRenderDevtools :spec="spec" :catalog="catalog" :messages="messages" />
</JSONUIProvider>
</template>
Svelte
<script>
import { JsonRenderDevtools } from "@json-render/devtools-svelte";
</script>
<JSONUIProvider {registry}>
<Renderer {spec} {registry} />
<JsonRenderDevtools {spec} {catalog} {messages} />
</JSONUIProvider>
Solid
import { JsonRenderDevtools } from "@json-render/devtools-solid";
<JSONUIProvider registry={registry}>
<Renderer spec={spec()} registry={registry} />
<JsonRenderDevtools
spec={spec()}
catalog={catalog}
messages={messages()}
/>
</JSONUIProvider>;
Controls
- Floating toggle appears bottom-right.
- Hotkey:
Ctrl/Cmd+Shift+J(configurable viahotkeyprop). - Drawer is resizable; height persists to localStorage.
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.
- yesterday First seen · 186 lines · 108 tokens per session scan A 3dacf170385b
devtools is a skill published in the GitHub repository vercel-labs/json-render (16,056 stars, last pushed 3d ago), licensed Apache-2.0. It adds 108 tokens to every session and 2,161 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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