New: 98,000+ skills indexed from GitHub repos with 100+ stars · every skill safety-checkedBrowse top skillsTop skills
Esc to closeBrowse all skills
Submit a skillBrowse skills
Submit a skillBrowse skills

Official agent skill

MCP Apps Builder

by awslabs in awslabs/cli-agent-orchestrator

Load the official MCP Apps builder skills (create-mcp-app, migrate-oai-app, add-app-to-server, convert-web-app) from github.com/modelcontextprotocol/ext-apps.

OfficialApache-2.0Auto-check passedAgent Workflows

Install MCP Apps Builder

skills CLI
$ npx skills add awslabs/cli-agent-orchestrator --skill mcp-apps-builder -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI
$ gh skill install awslabs/cli-agent-orchestrator mcp-apps-builder --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy
$ git clone --depth 1 https://github.com/awslabs/cli-agent-orchestrator.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/mcp-apps-builder .claude/skills/mcp-apps-builder && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Facts

Skill name
mcp-apps-builder
GitHub stars
1.4k
Token cost
~1.7k tokens
SKILL.md length
546 words
Files
5 (incl. scripts, references)
Skills in repo
14
Repo updated
First seen
Licence
Apache-2.0

At a glance

Load the official MCP Apps builder skills (create-mcp-app, migrate-oai-app, add-app-to-server, convert-web-app) from github.com/modelcontextprotocol/ext-apps.

  • The user says build an MCP App
  • SKILL.md covers The four builder skills, Install / load them, Building inside CAO (read this… and Sources of truth, plus 2 more sections
  • Runs Shell scripts from its folder; calls npm, npx and git; reaches github.com
  • Add a ui:// view to my MCP server

What it does

MCP Apps Builder is an agent skill from awslabs/cli-agent-orchestrator, published by the product's own GitHub organization. Load the official MCP Apps builder skills (create-mcp-app, migrate-oai-app, add-app-to-server, convert-web-app) from github.com/modelcontextprotocol/ext-apps. Use when the user says "build an MCP App", "add a ui:// view to my MCP server", "create an interactive MCP App from scratch", "migrate from OpenAI Apps SDK to MCP", or "turn my web app into a hybrid MCP App". Targets the MCP Apps SDK (SEP-1865 ui:// resources) specifically. Not for regular web frontends, REST APIs, CAO provider adapters, SKILL.md authoring…

Its SKILL.md is about 1.7k tokens, which your agent loads only when the skill is triggered. The skill folder holds 7 other files, including scripts and reference files (for example `evals/evals.json`, `references/cao-view-guardrails.md` and `references/installation-per-agent.md`). Compatibility notes: Requires Node.js for ext-apps skill installation. For CAO views, also requires CAOMCPAPPSENABLED=true.

It sits in Agent Workflows, covering MCP servers and REST APIs. It works with Model Context Protocol, OpenAI and GitHub. The repository describes itself as: Multi-agent orchestration for AI coding CLIs — Claude Code, Kiro, Codex, and more, coordinated in isolated tmux sessions. The licence is Apache-2.0.

When your agent uses it

  • The user says build an MCP App
  • Add a ui:// view to my MCP server
  • Create an interactive MCP App from scratch
  • Migrate from OpenAI Apps SDK to MCP

Example prompts

  • “build an MCP App”
  • “add a ui:// view to my MCP server”
  • “create an interactive MCP App from scratch”
  • “/mcp-apps-builder”

Requirements

  • Node.js
  • A Bash shell
  • Compatibility (from SKILL.md): Requires Node.js for ext-apps skill installation. For CAO views, also requires CAO_MCP_APPS_ENABLED=true.

What it can do on your machine

Read from SKILL.md and the folder at commit 089c53c. It shows what the files ask for, not the result of running them.

  • Tool permissions

    Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

    From allowed-tools in the SKILL.md frontmatter.

  • Runs code

    Ships 1 file in scripts/ (Shell), which the agent can run.

    Shell commands in SKILL.md call:

    • npm
    • npx
    • git

    From the folder's file list and the shell code blocks in SKILL.md.

  • Network

    Hosts in commands or code, which the agent is likely to contact:

    • github.com

    Also links to:

    • modelcontextprotocol.io
    • npmjs.com
    • apps.extensions.modelcontextprotocol.io

    From URLs in SKILL.md, links to its own repository left out.

  • Credentials

    Names no API keys, tokens, secrets or passwords.

    From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

  • Compatibility

    Requires Node.js for ext-apps skill installation. For CAO views, also requires CAO_MCP_APPS_ENABLED=true.

    From compatibility in the SKILL.md frontmatter.

Context cost

MCP Apps Builder loads about 1.7k tokens when it runs, and up to ~4.2k if it reads all its reference files. Until then it costs about 137 tokens; SKILL.md has 546 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it
~137
When it runs · the whole SKILL.md, loaded when a task matches
~1.7k
With references · SKILL.md plus every file in references/, read only if the agent opens them
~4.2k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); the scripts in this folder are not scanned.

SKILL.md

The full file from awslabs/cli-agent-orchestrator at commit 089c53c, republished under its Apache-2.0 licence (© awslabs). 546 words, ~1,673 tokens.

Download SKILL.mdSave it as .claude/skills/mcp-apps-builder/SKILL.md (or your agent's skills folder). This skill also uses 4 other files; get the full folder from GitHub.
name
mcp-apps-builder
description
Load the official MCP Apps builder skills (create-mcp-app, migrate-oai-app, add-app-to-server, convert-web-app) from github.com/modelcontextprotocol/ext-apps. Use when the user says "build an MCP App", "add a ui:// view to my MCP server", "create an interactive MCP App from scratch", "migrate from OpenAI Apps SDK to MCP", or "turn my web app into a hybrid MCP App". Targets the MCP Apps SDK (SEP-1865 ui:// resources) specifically. Not for regular web frontends, REST APIs, CAO provider adapters, SKILL.md authoring, or plugins.
compatibility
Requires Node.js for ext-apps skill installation. For CAO views, also requires CAO_MCP_APPS_ENABLED=true.

MCP Apps Builder (ext-apps Agent Skills bridge)

The Model Context Protocol ext-apps repo ships four official Agent Skills that teach an AI coding agent how to build MCP Apps (SEP-1865 — interactive ui:// UIs that render inside a chat host). This skill tells you when to reach for them and how to install them, so MCP App work is done with the canonical, up-to-date guidance instead of guesswork.

The four builder skills

SkillUse it when…
create-mcp-appScaffolding a new MCP App (server + interactive UI) from scratch.
add-app-to-serverAdding an interactive ui:// view to an existing MCP server's tools.
migrate-oai-appConverting an existing OpenAI Apps SDK app to MCP Apps.
convert-web-appTurning an existing web app into a hybrid web + MCP App.

Install / load them

Pick whichever matches the agent you're driving (skills live in the agent's skills directory — install once, then ask the agent to build):

  • Claude Code (plugin marketplace):
    /plugin marketplace add modelcontextprotocol/ext-apps
/plugin install mcp-apps@modelcontextprotocol-ext-apps
  • Any agent (Vercel Skills CLI):
    npx skills add modelcontextprotocol/ext-apps
  • Manual (clone + copy into the agent's skills dir):
    git clone https://github.com/modelcontextprotocol/ext-apps.git
cp -r ext-apps/plugins/mcp-apps/skills/create-mcp-app ~/.kiro/skills/create-mcp-app
# …repeat for add-app-to-server / migrate-oai-app / convert-web-app
    Skills dirs by agent: Kiro CLI ~/.kiro/skills/, Claude Code ~/.claude/skills/, VS Code/Copilot ~/.copilot/skills/, Gemini CLI ~/.gemini/skills/, Codex ~/.codex/skills/, Cursor ~/.cursor/skills/, Goose ~/.config/goose/skills/. Verify with: ask the agent "what skills do you have?"

For complete per-agent installation instructions and troubleshooting, see references/installation-per-agent.md.

Building inside CAO (read this for ui://cao/* work)

CAO's own views (ui://cao/dashboard / agent / event-stream) are hand-rolled single-file React bundles — not generated by create-mcp-app — because CAO enforces stricter invariants than the starter templates. When you add a new CAO view, use add-app-to-server's checklist for the spec-correct shape, but keep CAO's guardrails:

  • Default-off behind CAO_MCP_APPS_ENABLED (end to end).
  • JIT-free bundles (no eval / new Function; the host CSP forbids it; the scan:jit gate fails otherwise).
  • HTTP-only boundary: mcp_server/* reaches state only over HTTP (AST guard test/test_http_only_boundary.py).
  • Stay within the bundle-size budget (check:size) and the coverage ratchet (coverage:ratchet).
  • Tag tools with ui_meta(...) (resource _meta.ui: csp / permissions / domain / prefersBorder; tool _meta.ui: resourceUri / visibility).

For the full guardrail checklist and how to run each CI gate locally, see references/cao-view-guardrails.md.

For the operator/extend playbook (turn it on, troubleshoot, the submit_command choke point, host-delegated actions), load the cao-mcp-apps skill.

Show full SKILL.md (201 more words)Show less

Sources of truth

Gotchas

  • CAO views are NOT generated by create-mcp-app: CAO's own ui://cao/* views are hand-rolled single-file React bundles with stricter invariants than the starter templates. Use add-app-to-server for the spec-correct shape, but enforce CAO's guardrails (JIT-free, bundle-size budget, HTTP-only boundary).
  • JIT-free is non-negotiable for CAO: Host CSP forbids eval / new Function. The CI scan:jit gate will fail the build if any JIT constructs are present.
  • HTTP-only boundary: mcp_server/* must reach state only over HTTP to the Backplane. The AST guard test (test/test_http_only_boundary.py) enforces this — direct state access bypasses governance.

Build → Test → Record Workflow

When building or extending CAO MCP Apps views, always follow this complete cycle:

bash
cd cao_mcp_apps
npm run build:all         # Build all view bundles (single-file HTML)
npm test                  # Unit tests (vitest)
npm run test:e2e          # Playwright E2E against built bundles
npm run demo              # Record demo video + screenshots + GIF

The npm run demo step captures the current state of all views (including the unified fleet command center) into docs/media/ — this is what README.md and docs/mcp-apps.md display. Always regenerate after modifying views so documentation stays current.

For CAO-specific views (ui://cao/*), also verify:

  • Bundle size within budget: npm run check:size
  • No JIT constructs: npm run scan:jit
  • TypeScript strict: npx tsc --noEmit

For installation details per agent host, see references/installation-per-agent.md. For CAO view guardrails, see references/cao-view-guardrails.md.

© awslabs, Apache-2.0. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 4 other files (scripts, references) in skills/mcp-apps-builder of awslabs/cli-agent-orchestrator.

  • SKILL.md
  • evals/evals.json
  • references/cao-view-guardrails.md
  • references/installation-per-agent.md
  • scripts/validate.sh

Open the folder on GitHubat commit 089c53c

Compare with similar skills

MCP Apps Builder next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

MCP Apps Builder compared with similar skills
SkillStarsUsed inTokensAuto-checkLicenceRepo updated
MCP Apps Builder this skillawslabs/cli-agent-orchestrator1.4k—~1.7kAutomated safety check: PassApache-2.0
Openmaopenma-ai/open-managed-agents316—~854Automated safety check: PassApache-2.0
GitHub Commentingjuspay/neurolink144—~698Automated safety check: PassMIT
Docker Agent Deploydocker/skills547—~1.9kAutomated safety check: PassApache-2.0
Skill Seekers Builderyusufkaraaslan/Skill_Seekers15k—~760Automated safety check: PassMIT
Codex with ChatGPT Planning LoopXiaoDuoYa/codex-with-chatgpt7.1k—~11kAutomated safety check: NotesMIT

Similar skills

  • Openma

    openma-ai/open-managed-agents

    Use the openma platform to build, deploy, and manage AI agents.

    316 GitHub stars~854 tokensUpdated today
    AI & LLM EngineeringAuto-check passed

  • GitHub Commenting

    juspay/neurolink

    How to post clean, rich, deduplicated GitHub PR review comments — suggestion blocks, multi-line anchors, markers, formatting rules.

    144 GitHub stars~698 tokensUpdated today
    DevelopmentAuto-check passed

  • Docker Agent Deploy

    docker/skills

    Official

    A skill your agent uses when exposing a Docker Agent as a server (MCP, HTTP API, A2A, ACP, or OpenAI-compatible chat), distributing an agent via an OCI registry with docker agent share, or measuring…

    547 GitHub stars~1.9k tokensUpdated 4 days ago
    DevOps & CloudAuto-check passed

  • Skill Seekers Builder

    yusufkaraaslan/Skill_Seekers

    Detects the type of a knowledge source and uses the Skill Seekers MCP tools to turn docs, repos, PDFs or videos into packaged AI skills.

    15k GitHub stars~760 tokensUpdated 8 days ago
    Agent WorkflowsAuto-check passed

  • Codex with ChatGPT Planning Loop

    XiaoDuoYa/codex-with-chatgpt

    Uses ChatGPT in the browser as the planning and review brain for a Codex session, with Codex keeping all execution and ChatGPT reading the workspace through a bridge.

    7.1k GitHub stars~11k tokensUpdated 8 days ago
    Agent WorkflowsAuto-check: notes

  • Chatgpt Apps

    Haohao-end/openagent

    Build, scaffold, refactor, and troubleshoot ChatGPT Apps SDK applications that combine an MCP server and widget UI.

    808 GitHub starsUsed in 1 repo~4.9k tokens
    Agent WorkflowsAuto-check passed

More from awslabs/cli-agent-orchestrator

All 14 skills in this repo

  • Cao MCP Apps

    awslabs/cli-agent-orchestrator

    Official

    Enable, operate, and extend CAO's MCP Apps surface — the host-rendered fleet dashboard visible inside MCP App hosts (Claude Desktop, ChatGPT, VS Code Copilot, Goose, Postman).

    1.4k GitHub stars~1.9k tokensUpdated today
    Auto-check passed

  • Agui Author

    awslabs/cli-agent-orchestrator

    Official

    Author live dashboard UI from an agent via the emitui MCP tool.

    1.4k GitHub stars~2k tokensUpdated today
    Auto-check passed

  • Cao Plugin

    awslabs/cli-agent-orchestrator

    Official

    Create a new CAO (CLI Agent Orchestrator) plugin. An agent skill from awslabs/cli-agent-orchestrator.

    1.4k GitHub stars~3.1k tokensUpdated today
    Auto-check: notes

  • Cao Provider

    awslabs/cli-agent-orchestrator

    Official

    Create a new CLI agent provider for CAO (CLI Agent Orchestrator).

    1.4k GitHub stars~2.3k tokensUpdated today
    Auto-check passed

  • Cao Agent Routing

    awslabs/cli-agent-orchestrator

    Official

    Find and select the best installed CAO agent profile for a task before delegating with assign or handoff.

    1.4k GitHub stars~552 tokensUpdated today
    Auto-check passed

  • Cao Contributing

    awslabs/cli-agent-orchestrator

    Official

    Contribute changes to the CAO (CLI Agent Orchestrator) codebase — the local dev loop, the CI gate map, and the pre-PR checklist.

    1.4k GitHub stars~4.1k tokensUpdated today
    Auto-check passed

Works with

Categories

Questions about MCP Apps Builder

What does MCP Apps Builder do?

Load the official MCP Apps builder skills (create-mcp-app, migrate-oai-app, add-app-to-server, convert-web-app) from github.com/modelcontextprotocol/ext-apps. MCP Apps Builder is an agent skill from awslabs/cli-agent-orchestrator, published by the product's own GitHub organization.com/modelcontextprotocol/ext-apps.

When should I use MCP Apps Builder?

MCP Apps Builder fits situations like: the user says build an MCP App; add a ui:// view to my MCP server; create an interactive MCP App from scratch; migrate from OpenAI Apps SDK to MCP.

How do I install MCP Apps Builder in Claude Code?

Run `npx skills add awslabs/cli-agent-orchestrator --skill mcp-apps-builder -a claude-code`. Or copy the skill folder (skills/mcp-apps-builder in awslabs/cli-agent-orchestrator) into .claude/skills/mcp-apps-builder in your project. Claude Code loads it when a task matches its description.

How do I install MCP Apps Builder in Codex?

Run `npx skills add awslabs/cli-agent-orchestrator --skill mcp-apps-builder -a codex`. Or copy the skill folder (skills/mcp-apps-builder in awslabs/cli-agent-orchestrator) into .agents/skills/mcp-apps-builder in your project. Codex loads it when a task matches its description.

Can I use MCP Apps Builder in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add awslabs/cli-agent-orchestrator --skill mcp-apps-builder -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/mcp-apps-builder, .gemini/skills/mcp-apps-builder, .github/skills/mcp-apps-builder and .opencode/skills/mcp-apps-builder in your project.

What does MCP Apps Builder need to run?

Going by SKILL.md and its folder, MCP Apps Builder needs a shell for the scripts in its folder and the command-line tools its instructions call (npm, npx and git). Our summary lists: Node.js; A Bash shell. Compatibility (from SKILL.md): Requires Node.js for ext-apps skill installation. For CAO views, also requires CAO_MCP_APPS_ENABLED=true..

Does MCP Apps Builder access the network?

SKILL.md names 4 domains. In commands or code: github.com; the agent is likely to contact it when it follows the instructions. As links in the text: modelcontextprotocol.io, npmjs.com and apps.extensions.modelcontextprotocol.io. This is read from the text; nothing was executed.

Is MCP Apps Builder safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. The check reads SKILL.md only: the scripts in the folder are not scanned, so read them before running anything.

What licence does MCP Apps Builder use?

MCP Apps Builder is published under the Apache-2.0 licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does MCP Apps Builder use?

About 1.7k tokens (SKILL.md is roughly 6.7k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full. Its references folder adds about 2.5k tokens, read only when the agent opens those files.

What are the alternatives to MCP Apps Builder?

Skills that share tags, products or a category with MCP Apps Builder: Openma (openma-ai/open-managed-agents, 316 stars), GitHub Commenting (juspay/neurolink, 144 stars), Docker Agent Deploy (docker/skills, 547 stars) and Skill Seekers Builder (yusufkaraaslan/Skill_Seekers, 15k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains MCP Apps Builder?

awslabs (a GitHub organization, an official publisher) maintains it in awslabs/cli-agent-orchestrator, which has 1,400 GitHub stars. The repository holds 14 skills in this directory. The repository was last updated on October 9, 2026.

Source: awslabs/cli-agent-orchestrator on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.