What is mcp-apps-builder?

A skill for building, changing, troubleshooting, moving, or reviewing TypeScript MCP servers and interactive MCP Apps. MCP servers connect agents to tools and data, while MCP Apps can include interactive screens built with React.

Use it to work on MCP tools, resources, prompts, interactive Views, React host interactions, OAuth, middleware, Inspector checks, package boundaries, and release verification in mcp-use v2 projects.

It gives developers guidance for the parts of an MCP project that are easy to get wrong, including authentication, middleware, testing in Inspector, and package migrations.

How intheuniverseofaiz-eng/MCPDemo configures Codex

Reuse

Borrowing it

Nothing to install: this file belongs to intheuniverseofaiz-eng/MCPDemo. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/intheuniverseofaiz-eng/MCPDemo/main/.agents/skills/mcp-apps-builder/SKILL.md

Clone the repo

git clone --depth 1 https://github.com/intheuniverseofaiz-eng/MCPDemo

Made for: 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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/intheuniverseofaiz-eng/mcpdemo/mcp-apps-builder/github.svg)](https://agentmods.dev/skills/intheuniverseofaiz-eng/mcpdemo/mcp-apps-builder)

Your own site

<a href="https://agentmods.dev/skills/intheuniverseofaiz-eng/mcpdemo/mcp-apps-builder"><img src="https://agentmods.dev/badge/skills/intheuniverseofaiz-eng/mcpdemo/mcp-apps-builder/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/intheuniverseofaiz-eng/mcpdemo/mcp-apps-builder"><img src="https://agentmods.dev/badge/skills/intheuniverseofaiz-eng/mcpdemo/mcp-apps-builder.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 68 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,052 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 unknown 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.

Model	Per session	Once invoked
Fable 5.1	$0.00068	$0.01052
Opus 5.5	$0.00027	$0.00421
Sonnet 5.5	$0.00014	$0.00210
Haiku 4.5	$0.00007	$0.00105

Measured 2mo ago against content hash 3035e65e2134, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

mcp-apps-builder 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 2mo ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/check-v2.mjs), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

.agents/skills/mcp-apps-builder/SKILL.md · 91 lines

The source is not reproduced here

No licence file

Read it on GitHub

Files

What ships with it

8 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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.

2mo ago First seen · 91 lines · 68 tokens per session scan A 3035e65e2134

Subscribe to this mod's changes

mcp-apps-builder is a skill published in the GitHub repository intheuniverseofaiz-eng/MCPDemo (0 stars, last pushed 2mo ago), with no licence file. It adds 68 tokens to every session and 1,052 once invoked, about $0.0003 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 2026-08-31.

Building agents Languages TypeScript

mcp-apps-builder next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
mcp-apps-builderintheuniverseofaiz-eng/MCPDemo	Skill	0	2mo ago	none	A	68	Codex
no-bare-castsprisma/orm	Skill	48k	today	Apache-2.0	A	52	Claude Code, Codex
aws-sst-developmentsickn33/agentic-awesome-skills	Skill	49k	today	MIT	A	26	Claude Code
league-akari-shard-developmentLeagueAkari/LeagueAkari	Skill	4.7k	5d ago	MIT	A	58	Claude Code, Codex
dd-code-generationDataDog/pup	Skill	1.0k	today	Apache-2.0	A	16	Claude Code
fast-typescript-checkinternet-development/www-sacred	Skill	1.6k	3d ago	MIT	A	84	Claude Code, Codex
typescript-magicianmcollina/skills	Skill	2.0k	10d ago	MIT	A	108	Claude Code, Codex

MCPDemo: Skill for Codex