Borrowing it
Nothing to install: this file belongs to ZenlixAI/echo-mcp. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/ZenlixAI/echo-mcp/main/.agents/skills/mcp-apps-builder/SKILL.mdgit clone --depth 1 https://github.com/ZenlixAI/echo-mcpWrote 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.
[](https://agentmods.dev/skills/zenlixai/echo-mcp/mcp-apps-builder)<a href="https://agentmods.dev/skills/zenlixai/echo-mcp/mcp-apps-builder"><img src="https://agentmods.dev/badge/skills/zenlixai/echo-mcp/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.
<a href="https://agentmods.dev/skills/zenlixai/echo-mcp/mcp-apps-builder"><img src="https://agentmods.dev/badge/skills/zenlixai/echo-mcp/mcp-apps-builder.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00139 | $0.03484 |
| Opus 5.5 | $0.00056 | $0.01394 |
| Sonnet 5.5 | $0.00028 | $0.00697 |
| Haiku 4.5 | $0.00014 | $0.00348 |
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 1mo 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.
This is a copy
88% identical to mcp-apps-builder — 86 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 374 lines — stays where its author put it; the contents beside it link to each section on GitHub.
IMPORTANT: How to Use This Skill
This file provides a NAVIGATION GUIDE ONLY. Before implementing any MCP server features, you MUST:
- Read this overview to understand which reference files are relevant
- ALWAYS read the specific reference file(s) for the features you're implementing
- Apply the detailed patterns from those files to your implementation
Do NOT rely solely on the quick reference examples in this file - they are minimal examples only. The reference files contain critical best practices, security considerations, and advanced patterns.
MCP Server Best Practices
Comprehensive guide for building production-ready MCP servers with tools, resources, prompts, and widgets using mcp-use.
⚠️ FIRST: New Project or Existing Project?
Before doing anything else, determine whether you are inside an existing mcp-use project.
Detection: Check the workspace for a package.json that lists "mcp-use" as a dependency, OR any .ts file that imports from "mcp-use/server".
├─ mcp-use project FOUND → Do NOT scaffold. You are already in a project.
│ └─ Skip to "Quick Navigation" below to add features.
│
├─ NO mcp-use project (empty dir, unrelated project, or greenfield)
│ └─ Scaffold first with npx create-mcp-use-app, then add features.
│ See "Scaffolding a New Project" below.
│
└─ Inside an UNRELATED project (e.g. Next.js app) and user wants an MCP server
└─ Ask the user where to create it, then scaffold in that directory.
Do NOT scaffold inside an existing unrelated project root.
NEVER manually create MCPServer boilerplate, package.json, or project structure by hand. The CLI sets up TypeScript config, dev scripts, inspector integration, hot reload, and widget compilation that are difficult to replicate manually.
Scaffolding a New Project
npx create-mcp-use-app my-server
cd my-server
npm run dev
For full scaffolding details and CLI flags, see quickstart.md.
What ships with it
22 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.
- LICENSE.txt 8.9 KB
- references/authentication/custom.md 6.4 KB
- references/authentication/overview.md 6.4 KB
- references/authentication/supabase.md 5.0 KB
- references/authentication/workos.md 6.1 KB
- references/foundations/architecture.md 8.3 KB
- references/foundations/concepts.md 3.3 KB
- references/foundations/deployment.md 2.6 KB
- references/foundations/quickstart.md 6.0 KB
- references/patterns/common-patterns.md 21 KB
- references/server/prompts.md 16 KB
- references/server/proxy.md 3.2 KB
- references/server/resources.md 11 KB
- references/server/response-helpers.md 12 KB
- references/server/tools.md 13 KB
- references/widgets/advanced.md 19 KB
- references/widgets/basics.md 18 KB
- references/widgets/files.md 4.7 KB
- references/widgets/interactivity.md 22 KB
- references/widgets/model-context.md 5.4 KB
- references/widgets/state.md 16 KB
- references/widgets/ui-guidelines.md 15 KB
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.
- 1mo ago First seen · 374 lines · 139 tokens per session scan A 9c847ecd6cef
mcp-apps-builder is a skill published in the GitHub repository ZenlixAI/echo-mcp (8 stars, last pushed 6mo ago), licensed MIT. It adds 139 tokens to every session and 3,484 once invoked, about $0.0006 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 88% identical to mcp-apps-builder, differing in 86 lines, and is treated as a copy.
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