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.
Review an MCP tool implementation for correctness, pattern adherence, and best practices.
Install Tool Review
$ npx skills add nesquikm/mcp-rubber-duck --skill tool-review -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install nesquikm/mcp-rubber-duck tool-review --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/nesquikm/mcp-rubber-duck.git skills-src && mkdir -p .claude/skills && cp -r skills-src/.claude/skills/tool-review .claude/skills/tool-review && 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 "tool-review" agent skill from https://github.com/nesquikm/mcp-rubber-duck/tree/master/.claude/skills/tool-review into .claude/skills/tool-review/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "tool-review", 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/nesquikm/mcp-rubber-duck/tree/master/.claude/skills/tool-reviewType 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 nesquikm/mcp-rubber-duck --skill tool-review -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install nesquikm/mcp-rubber-duck tool-review --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/nesquikm/mcp-rubber-duck.git skills-src && mkdir -p .agents/skills && cp -r skills-src/.claude/skills/tool-review .agents/skills/tool-review && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "tool-review" agent skill from https://github.com/nesquikm/mcp-rubber-duck/tree/master/.claude/skills/tool-review into .agents/skills/tool-review/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "tool-review", 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 nesquikm/mcp-rubber-duck --skill tool-review -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install nesquikm/mcp-rubber-duck tool-review --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/nesquikm/mcp-rubber-duck.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/.claude/skills/tool-review .cursor/skills/tool-review && 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 "tool-review" agent skill from https://github.com/nesquikm/mcp-rubber-duck/tree/master/.claude/skills/tool-review into .cursor/skills/tool-review/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "tool-review", 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/nesquikm/mcp-rubber-duck.git --path .claude/skills/tool-review--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 nesquikm/mcp-rubber-duck --skill tool-review -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install nesquikm/mcp-rubber-duck tool-review --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/nesquikm/mcp-rubber-duck.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/.claude/skills/tool-review .gemini/skills/tool-review && 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 "tool-review" agent skill from https://github.com/nesquikm/mcp-rubber-duck/tree/master/.claude/skills/tool-review into .gemini/skills/tool-review/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "tool-review", 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 nesquikm/mcp-rubber-duck tool-reviewInstalls 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 nesquikm/mcp-rubber-duck --skill tool-review -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/nesquikm/mcp-rubber-duck.git skills-src && mkdir -p .github/skills && cp -r skills-src/.claude/skills/tool-review .github/skills/tool-review && 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 "tool-review" agent skill from https://github.com/nesquikm/mcp-rubber-duck/tree/master/.claude/skills/tool-review into .github/skills/tool-review/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "tool-review", 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 nesquikm/mcp-rubber-duck --skill tool-review -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install nesquikm/mcp-rubber-duck tool-review --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/nesquikm/mcp-rubber-duck.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/.claude/skills/tool-review .opencode/skills/tool-review && 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 "tool-review" agent skill from https://github.com/nesquikm/mcp-rubber-duck/tree/master/.claude/skills/tool-review into .opencode/skills/tool-review/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "tool-review", 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
tool-review- GitHub stars
- 178
- Token cost
- ~420 tokens
- SKILL.md length
- 186 words
- Files
- 1
- Skills in repo
- 3
- Repo updated
- First seen
- Licence
- MIT
At a glance
Review an MCP tool implementation for correctness, pattern adherence, and best practices.
- Works in 4 steps: Locate the tool → Check against project patterns → Check for common issues → …
- Tasks that involve MCP servers
- Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
What it does
Tool Review is an agent skill from nesquikm/mcp-rubber-duck. Review an MCP tool implementation for correctness, pattern adherence, and best practices. Use after implementing or modifying a tool.
Its SKILL.md is about 420 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. The repository describes itself as: An MCP server that acts as a bridge to query multiple OpenAI-compatible LLMs with MCP tool access. Just like rubber duck debugging, explain your problems to various AI "ducks"… The licence is MIT.
When your agent uses it
- Tasks that involve MCP servers
Example prompts
- “/tool-review”
Requirements
- Pre-approved tools (allowed-tools): Read, Grep, Glob
Workflow steps
4 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 4e321d9. 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:
ReadGrepGlob
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
Tool Review loads about 420 tokens when it runs. Until then it costs about 36 tokens; SKILL.md has 186 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 nesquikm/mcp-rubber-duck at commit 4e321d9, republished under its MIT licence (© nesquikm). 186 words, ~420 tokens.
Download SKILL.mdSave it as
.claude/skills/tool-review/SKILL.md (or your agent's skills folder).- name
- tool-review
- description
- Review an MCP tool implementation for correctness, pattern adherence, and best practices. Use after implementing or modifying a tool.
- allowed-tools
- Read, Grep, Glob
- argument-hint
- <tool-name or file path>
Tool Review
Review the MCP tool implementation for: $ARGUMENTS
Process
1. Locate the tool
Find the tool implementation in src/tools/ and its registration in src/server.ts.
2. Check against project patterns
Verify each of these (from CLAUDE.md):
Response format:
- Returns
{ content: [{ type: 'text', text: '...' }] }on success - Returns
{ content: [{ type: 'text', text: 'Error: ...' }], isError: true }on error
Input validation:
- Required arguments are checked with clear error messages
- Uses appropriate types from Zod schemas where applicable
Registration in server.ts:
- Tool is imported with
.jsextension in the import path - Added to
getTools()array with correct JSON Schema for inputs - Has a case in the
CallToolRequestSchemahandler switch
Dependencies:
- Uses the right dependencies (providerManager, conversationManager, healthMonitor, etc.)
- Follows the same injection pattern as existing tools
3. Check for common issues
- Missing error handling for provider calls
- Hardcoded values that should come from config
- Missing or incorrect TypeScript types
- Security issues (unsanitized input, injection risks)
4. Report
For each check:
- ✓ Pass — follows the pattern correctly
- ✗ Fail — what's wrong and how to fix it
- ⚠ Warning — works but could be improved
End with a summary: APPROVED or NEEDS CHANGES with specific action items.
© nesquikm, 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 .claude/skills/tool-review of nesquikm/mcp-rubber-duck.
Open the folder on GitHubat commit 4e321d9
Compare with similar skills
Tool Review 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 |
|---|---|---|---|---|---|---|
| Tool Review this skillnesquikm/mcp-rubber-duck | 178 | — | ~420 | 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 | 4 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 | |
| Microsoft Skill CreatorMicrosoftDocs/mcp | 1.9k | 3 repos | ~2.1k | Automated safety check: Pass | CC-BY-4.0 | |
| Crush Configurationcharmbracelet/crush | 29k | — | ~3.7k | Automated safety check: Pass | Custom licence |
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- Official
MCP Integration for Plugins
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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.
- Official
Microsoft Skill Creator
MicrosoftDocs/mcp
Create agent skills for Microsoft technologies using official documentation.
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
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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.
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Related
Categories
Questions about Tool Review
What does Tool Review do?
Review an MCP tool implementation for correctness, pattern adherence, and best practices. Tool Review is an agent skill from nesquikm/mcp-rubber-duck. Review an MCP tool implementation for correctness, pattern adherence, and best practices.
When should I use Tool Review?
Tool Review fits situations like: tasks that involve MCP servers.
How do I install Tool Review in Claude Code?
Run `npx skills add nesquikm/mcp-rubber-duck --skill tool-review -a claude-code`. Or copy the skill folder (.claude/skills/tool-review in nesquikm/mcp-rubber-duck) into .claude/skills/tool-review in your project. Claude Code loads it when a task matches its description.
How do I install Tool Review in Codex?
Run `npx skills add nesquikm/mcp-rubber-duck --skill tool-review -a codex`. Or copy the skill folder (.claude/skills/tool-review in nesquikm/mcp-rubber-duck) into .agents/skills/tool-review in your project. Codex loads it when a task matches its description.
Can I use Tool Review 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 nesquikm/mcp-rubber-duck --skill tool-review -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/tool-review, .gemini/skills/tool-review, .github/skills/tool-review and .opencode/skills/tool-review in your project.
What does Tool Review need to run?
SKILL.md names no scripts, command-line tools or credentials: Tool Review is instructions for the agent only. Its frontmatter pre-approves these tools: Read, Grep, Glob.
Does Tool Review 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 Tool Review 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 Tool Review use?
Tool Review 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 Tool Review use?
About 420 tokens (SKILL.md is roughly 1.7k 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 Tool Review?
Skills that share tags, products or a category with Tool Review: 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 Microsoft Skill Creator (MicrosoftDocs/mcp, 1.9k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Tool Review?
nesquikm (a GitHub user) maintains it in nesquikm/mcp-rubber-duck, which has 178 GitHub stars. The repository holds 3 skills in this directory. The repository was last updated on October 9, 2026.
Source: nesquikm/mcp-rubber-duck on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.