mcp-apps-builder

mcp-apps-builder is a skill for Claude Code, Codex from guillermoscript/lms-front. It costs 55 tokens per session (774 once invoked), scanned A, original, MIT.

A development guide for TypeScript MCP servers and interactive MCP Apps built with mcp-use version 2. MCP servers provide tools, data, or prompts that AI clients can use, while MCP Apps can show interactive views.

In plain words
What is it for?
Use it to create or modify tools, resources, prompts, interactive React views, authentication, middleware, and release checks in an mcp-use project.
Why use it?
It gives a version-aware workflow for building, migrating, debugging, and checking these projects against their installed package and types.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/guillermoscript/lms-front/mcp-apps-builder
Any agent
npx skills add guillermoscript/lms-front --skill mcp-apps-builder
Clone the repo
git clone --depth 1 https://github.com/guillermoscript/lms-front

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 mcp-apps-builder

README.md
[![agentmods](https://agentmods.dev/badge/skills/guillermoscript/lms-front/mcp-apps-builder.svg)](https://agentmods.dev/skills/guillermoscript/lms-front/mcp-apps-builder)
Your own site
<a href="https://agentmods.dev/skills/guillermoscript/lms-front/mcp-apps-builder"><img src="https://agentmods.dev/badge/skills/guillermoscript/lms-front/mcp-apps-builder.svg" alt="Measured on agentmods" height="20"></a>
Per session 55 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 774 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00055 $0.00774
Opus 5 $0.00028 $0.00387
Sonnet 5 $0.00011 $0.00155
Haiku 4.5 $0.00006 $0.00077

Measured today against content hash b65c2719ae16, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, 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 today.

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.

Origin

Copies of this mod

1 near-identical copy found in the catalogue:

.agents/skills/mcp-apps-builder/SKILL.md · 44 lines

How it starts

The opening of the file, as written. The whole thing — 44 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Build with mcp-use

Treat the installed mcp-use package, its exported types, generated declarations, and the project's existing code as the source of truth. Inspect the installed version before choosing APIs or changing code.

Workflow

  1. Inspect package.json, the server entry, exported tool refs, mcp-env.d.ts, views/, skills/, and the installed mcp-use version.
  2. Scaffold a new stable project with create-mcp-use-app@latest and the appropriate template. Match the package version or dist-tag when working on beta, canary, or an existing versioned project.
  3. Read only the references needed for the task:
    • Server for tools, resources, prompts, MCP middleware, request context, and result envelopes.
    • Views for interactive MCP Apps, React hooks, model context, host capabilities, assets, and CSP.
    • Authentication for OAuth providers, verified identity, scopes, permissions, and authorization.
    • Skills over MCP when a server should ship reusable workflows alongside its tools.
    • Advanced features for OpenAPI, proxying, notifications, subscriptions, and elicitation.
    • Migration only when retired or compatibility-only imports, helpers, registration shapes, UI patterns, or session assumptions are present.
    • Verification before reporting implementation work complete.
  4. Implement against installed types. Prefer the framework's current conventions over copied examples or historical changelogs.
  5. Validate the smallest real lifecycle that proves the changed behavior, then expand checks in proportion to risk.

Core invariants

  • Import server APIs from mcp-use, React APIs from mcp-use/react, and OAuth provider adapters from their mcp-use/oauth/* subpaths.
  • Define tool arguments with inputSchema. Add outputSchema for structured results and every View-bound tool.
  • Return raw MCP result envelopes. A successful schema-backed tool must include matching structuredContent; an expected failure may return isError: true with model-readable content.
  • Put each View at views/<name>/view.tsx and bind it with view: { name: "<name>" }.
  • Export every statically declared tool ref consumed by a View. Default-export the server entry used by mcp-use dev, build, and start.
  • Keep identity and mutable workflow state request-scoped or in an external store. Treat client-reported metadata as unverified.
  • Consider Skills over MCP when a server exposes a repeatable, multi-step workflow that would otherwise inflate tool descriptions.

Read the full file on GitHub · 44 lines

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.

  1. today Changed · -47 lines · -13 tokens per session b65c2719ae16
  2. 4d 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 guillermoscript/lms-front (25 stars, last pushed yesterday), licensed MIT. It adds 55 tokens to every session and 774 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.

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