MCP Server Builder
anthropics/skills
Guides the design and implementation of Model Context Protocol servers in TypeScript or Python, from tool naming and error messages to evaluation.
MCP (Model Context Protocol) server building principles. An agent skill from xenitV1/Antigravity-Workflows.
Install MCP Builder
$ npx skills add xenitV1/Antigravity-Workflows --skill mcp-builder -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install xenitV1/Antigravity-Workflows mcp-builder --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/xenitV1/Antigravity-Workflows.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/mcp-builder .claude/skills/mcp-builder && rm -rf skills-srcUse ~/.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/
Install the "mcp-builder" agent skill from https://github.com/xenitV1/Antigravity-Workflows/tree/main/skills/mcp-builder into .claude/skills/mcp-builder/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "mcp-builder", then confirm the skill loads.Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$skill-installer install https://github.com/xenitV1/Antigravity-Workflows/tree/main/skills/mcp-builderType this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
$ npx skills add xenitV1/Antigravity-Workflows --skill mcp-builder -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install xenitV1/Antigravity-Workflows mcp-builder --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/xenitV1/Antigravity-Workflows.git skills-src && mkdir -p .agents/skills && cp -r skills-src/skills/mcp-builder .agents/skills/mcp-builder && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "mcp-builder" agent skill from https://github.com/xenitV1/Antigravity-Workflows/tree/main/skills/mcp-builder into .agents/skills/mcp-builder/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "mcp-builder", then confirm the skill loads.Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add xenitV1/Antigravity-Workflows --skill mcp-builder -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install xenitV1/Antigravity-Workflows mcp-builder --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/xenitV1/Antigravity-Workflows.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/skills/mcp-builder .cursor/skills/mcp-builder && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "mcp-builder" agent skill from https://github.com/xenitV1/Antigravity-Workflows/tree/main/skills/mcp-builder into .cursor/skills/mcp-builder/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "mcp-builder", then confirm the skill loads.Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gemini skills install https://github.com/xenitV1/Antigravity-Workflows.git --path skills/mcp-builder--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add xenitV1/Antigravity-Workflows --skill mcp-builder -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install xenitV1/Antigravity-Workflows mcp-builder --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/xenitV1/Antigravity-Workflows.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/skills/mcp-builder .gemini/skills/mcp-builder && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "mcp-builder" agent skill from https://github.com/xenitV1/Antigravity-Workflows/tree/main/skills/mcp-builder into .gemini/skills/mcp-builder/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "mcp-builder", then confirm the skill loads.Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gh skill install xenitV1/Antigravity-Workflows mcp-builderInstalls for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
$ npx skills add xenitV1/Antigravity-Workflows --skill mcp-builder -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/xenitV1/Antigravity-Workflows.git skills-src && mkdir -p .github/skills && cp -r skills-src/skills/mcp-builder .github/skills/mcp-builder && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "mcp-builder" agent skill from https://github.com/xenitV1/Antigravity-Workflows/tree/main/skills/mcp-builder into .github/skills/mcp-builder/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "mcp-builder", then confirm the skill loads.GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add xenitV1/Antigravity-Workflows --skill mcp-builder -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install xenitV1/Antigravity-Workflows mcp-builder --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/xenitV1/Antigravity-Workflows.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/skills/mcp-builder .opencode/skills/mcp-builder && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "mcp-builder" agent skill from https://github.com/xenitV1/Antigravity-Workflows/tree/main/skills/mcp-builder into .opencode/skills/mcp-builder/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "mcp-builder", then confirm the skill loads.OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
Facts
- Skill name
mcp-builder- GitHub stars
- 130
- Token cost
- ~821 tokens
- SKILL.md length
- 301 words
- Files
- 1
- Skills in repo
- 42
- Repo updated
- First seen
- Licence
- MIT
At a glance
MCP (Model Context Protocol) server building principles. An agent skill from xenitV1/Antigravity-Workflows.
- Works in 10 steps: MCP Overview → Server Architecture → Tool Design Principles → …
- Tasks that involve MCP servers
- SKILL.md covers 1. MCP Overview, 2. Server Architecture, 3. Tool Design Principles and 4. Resource Patterns, plus 6 more sections
- Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
What it does
MCP Builder is an agent skill from xenitV1/Antigravity-Workflows. MCP (Model Context Protocol) server building principles. Tool design, resource patterns, best practices.
Its SKILL.md is about 820 tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.
It sits in Agent Workflows, covering MCP servers. It works with Model Context Protocol. The licence is MIT.
When your agent uses it
- Tasks that involve MCP servers
Example prompts
- “/mcp-builder”
Requirements
- Pre-approved tools (allowed-tools): Read, Write, Edit, Glob, Grep
Workflow steps
10 steps, taken from the step headings in SKILL.md.
What it can do on your machine
Read from SKILL.md and the folder at commit f0a1fa7. It shows what the files ask for, not the result of running them.
Tool permissions
Pre-approves these tools, so the agent can use them without asking each time:
ReadWriteEditGlobGrep
From allowed-tools in the SKILL.md frontmatter.
Runs code
No scripts in the folder and no shell commands in SKILL.md.
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md.
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.
Context cost
MCP Builder loads about 821 tokens when it runs. Until then it costs about 29 tokens; SKILL.md has 301 words of instructions outside code blocks.
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); files beside SKILL.md are not scanned.
SKILL.md
The full file from xenitV1/Antigravity-Workflows at commit f0a1fa7, republished under its MIT licence (© xenitV1). 301 words, ~821 tokens.
Download SKILL.mdSave it as
.claude/skills/mcp-builder/SKILL.md (or your agent's skills folder).- name
- mcp-builder
- description
- MCP (Model Context Protocol) server building principles. Tool design, resource patterns, best practices.
- allowed-tools
- Read, Write, Edit, Glob, Grep
MCP Builder
Principles for building MCP servers.
1. MCP Overview
What is MCP?
Model Context Protocol - standard for connecting AI systems with external tools and data sources.
Core Concepts
| Concept | Purpose |
|---|---|
| Tools | Functions AI can call |
| Resources | Data AI can read |
| Prompts | Pre-defined prompt templates |
2. Server Architecture
Project Structure
my-mcp-server/
├── src/
│ └── index.ts # Main entry
├── package.json
└── tsconfig.jsonTransport Types
| Type | Use |
|---|---|
| Stdio | Local, CLI-based |
| SSE | Web-based, streaming |
| WebSocket | Real-time, bidirectional |
3. Tool Design Principles
Good Tool Design
| Principle | Description |
|---|---|
| Clear name | Action-oriented (get_weather, create_user) |
| Single purpose | One thing well |
| Validated input | Schema with types and descriptions |
| Structured output | Predictable response format |
Input Schema Design
| Field | Required? |
|---|---|
| Type | Yes - object |
| Properties | Define each param |
| Required | List mandatory params |
| Description | Human-readable |
4. Resource Patterns
Resource Types
| Type | Use |
|---|---|
| Static | Fixed data (config, docs) |
| Dynamic | Generated on request |
| Template | URI with parameters |
URI Patterns
| Pattern | Example |
|---|---|
| Fixed | docs://readme |
| Parameterized | users://{userId} |
| Collection | files://project/* |
5. Error Handling
Error Types
| Situation | Response |
|---|---|
| Invalid params | Validation error message |
| Not found | Clear "not found" |
| Server error | Generic error, log details |
Best Practices
- Return structured errors
- Don't expose internal details
- Log for debugging
- Provide actionable messages
6. Multimodal Handling
Supported Types
| Type | Encoding |
|---|---|
| Text | Plain text |
| Images | Base64 + MIME type |
| Files | Base64 + MIME type |
7. Security Principles
Input Validation
- Validate all tool inputs
- Sanitize user-provided data
- Limit resource access
API Keys
- Use environment variables
- Don't log secrets
- Validate permissions
8. Configuration
Claude Desktop Config
| Field | Purpose |
|---|---|
| command | Executable to run |
| args | Command arguments |
| env | Environment variables |
9. Testing
Test Categories
| Type | Focus |
|---|---|
| Unit | Tool logic |
| Integration | Full server |
| Contract | Schema validation |
10. Best Practices Checklist
- Clear, action-oriented tool names
- Complete input schemas with descriptions
- Structured JSON output
- Error handling for all cases
- Input validation
- Environment-based configuration
- Logging for debugging
Remember: MCP tools should be simple, focused, and well-documented. The AI relies on descriptions to use them correctly.
© xenitV1, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file
Files
Just SKILL.md in skills/mcp-builder of xenitV1/Antigravity-Workflows.
Open the folder on GitHubat commit f0a1fa7
Compare with similar skills
MCP 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.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| MCP Builder this skillxenitV1/Antigravity-Workflows | 130 | — | ~821 | Automated safety check: Pass | MIT | |
| MCP Server Builderanthropics/skills | 180k | 63 repos | ~2.3k | Automated safety check: Pass | Apache-2.0 | |
| MCP Server BuildershareAI-lab/learn-claude-code | 78k | 5 repos | ~1.2k | Automated safety check: Pass | MIT | |
| MCP Integration for Pluginsanthropics/claude-plugins-official | 38k | 11 repos | ~3.1k | Automated safety check: Pass | Apache-2.0 | |
| Crush Configurationcharmbracelet/crush | 29k | — | ~3.7k | Automated safety check: Pass | Custom licence | |
| Context Mode Output Sandboxmksglu/context-mode | 26k | — | ~4.1k | Automated safety check: Pass | Custom licence |
Similar skills
- Official
MCP Server Builder
shareAI-lab/learn-claude-code
Walks through building MCP servers in Python or TypeScript that expose tools, resources and prompts to Claude, with templates, registration and testing.
- Official
MCP Integration for Plugins
anthropics/claude-plugins-official
Explains how to bundle Model Context Protocol servers in a Claude Code plugin, covering config files, stdio, SSE, HTTP and WebSocket server types, and authentication.
Crush Configuration
charmbracelet/crush
Explains how to configure the Crush coding agent with crushrc or crush.json, covering providers, models, LSPs, MCP servers, hooks, permissions and config precedence.
Context Mode Output Sandbox
mksglu/context-mode
Routes large command, file, API and browser output through context-mode tools so only the needed result enters the agent's context, instead of dumping it via Bash.
Warp GUI to Agent CLI Migration
warpdotdev/warp
Migrates the compatible subset of settings and global file-based MCP servers from the Warp desktop app into Warp Agent CLI without exposing credentials or state.
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Questions about MCP Builder
What does MCP Builder do?
MCP (Model Context Protocol) server building principles. An agent skill from xenitV1/Antigravity-Workflows. MCP Builder is an agent skill from xenitV1/Antigravity-Workflows. MCP (Model Context Protocol) server building principles.
When should I use MCP Builder?
MCP Builder fits situations like: tasks that involve MCP servers.
How do I install MCP Builder in Claude Code?
Run `npx skills add xenitV1/Antigravity-Workflows --skill mcp-builder -a claude-code`. Or copy the skill folder (skills/mcp-builder in xenitV1/Antigravity-Workflows) into .claude/skills/mcp-builder in your project. Claude Code loads it when a task matches its description.
How do I install MCP Builder in Codex?
Run `npx skills add xenitV1/Antigravity-Workflows --skill mcp-builder -a codex`. Or copy the skill folder (skills/mcp-builder in xenitV1/Antigravity-Workflows) into .agents/skills/mcp-builder in your project. Codex loads it when a task matches its description.
Can I use MCP 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 xenitV1/Antigravity-Workflows --skill mcp-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-builder, .gemini/skills/mcp-builder, .github/skills/mcp-builder and .opencode/skills/mcp-builder in your project.
What does MCP Builder need to run?
SKILL.md names no scripts, command-line tools or credentials: MCP Builder is instructions for the agent only. Its frontmatter pre-approves these tools: Read, Write, Edit, Glob, Grep.
Does MCP Builder access the network?
SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.
Is MCP 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. Review the folder before installing.
What licence does MCP Builder use?
MCP Builder is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.
How many tokens does MCP Builder use?
About 821 tokens (SKILL.md is roughly 3.3k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.
What are the alternatives to MCP Builder?
Skills that share tags, products or a category with MCP Builder: MCP Server Builder (anthropics/skills, 180k stars), MCP Server Builder (shareAI-lab/learn-claude-code, 78k stars), MCP Integration for Plugins (anthropics/claude-plugins-official, 38k stars) and Crush Configuration (charmbracelet/crush, 29k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains MCP Builder?
xenitV1 (a GitHub user) maintains it in xenitV1/Antigravity-Workflows, which has 130 GitHub stars. The repository holds 42 skills in this directory. The repository was last updated on January 14, 2026.
Source: xenitV1/Antigravity-Workflows on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.