mcp-developer
An agent skill by Jeffallan, from Jeffallan/claude-skills. Tags: api, automation, debugging, developer-tools, mcp.
What it does
Use when building, debugging, or extending MCP servers or clients that connect AI systems with external tools and data sources. Invoke to implement tool handlers, configure resource providers, set up stdio/HTTP/SSE transport layers, validate schemas with Zod or Pydantic, debug protocol compliance issues, or scaffold complete MCP server/client projects using TypeScript or Python SDKs.
Install
With the skills CLI, which installs into Claude Code, Codex, Cursor and other agents:
npx skills add Jeffallan/claude-skills --skill mcp-developerOr copy the skill folder into Claude Code's skills directory by hand (~/.claude/skills for every project, or .claude/skills inside one):
git clone --depth 1 https://github.com/Jeffallan/claude-skills
cp -r claude-skills/skills/mcp-developer ~/.claude/skills/mcp-developerSafety box score
Grade B, low risk: 18 of 100 risk points, rated 2026-10-19. The grade rates what the skill and its scripts can reach on the machine of whoever installs it, across eight categories from shell execution to secrets access. How the score works.
This is a docs-only skill for building MCP servers and clients. Its main risk is that it directs the agent to install and run registry packages and to build networked integrations that can expose local files or external data sources, depending on the implementation the agent produces.
| Category | Level | Why |
|---|---|---|
| Code & shell execution | 2 (moderate) | The core workflow tells the agent to run shell commands like `npx @modelcontextprotocol/create-server my-server`, `pip install mcp`, and `npx @modelcontextprotocol/inspector`, which executes registry-fetched tooling. |
| Network access | 2 (moderate) | It is explicitly about connecting to external tools/data sources and includes HTTP/SSE transport plus package installs from npm/PyPI, so the generated implementations will commonly send and receive data over the network. |
| Filesystem reach | 1 (low) | The examples read local repository and file-backed resources such as `file:///config/settings.json` and `git.Repo(".")`, but the skill does not itself write or delete outside the project. |
| Secrets & credentials | 0 (none) | It mentions auth and env vars and warns not to hardcode secrets, but it does not request, read, or exfiltrate credentials itself. |
| Privilege & persistence | 0 (none) | No sudo, global OS changes, service registration, or shell startup edits are shown. |
| Instruction hijack surface | 0 (none) | There is no instruction to ignore safeguards, follow hidden remote content, or hide actions from the user; the references are local markdown files. |
| Irreversible actions | 0 (none) | The skill is for implementation and testing, not for pushing, publishing, paying, booking, or deleting on its own. |
| Transparency | 0 (none) | All shipped files are plain text markdown; there are no binaries, packed installers, or decoded-at-runtime blobs. |
Before installing
- Read `SKILL.md` and confirm you are comfortable running `npx`/`pip install` commands that fetch packages from registries.
- Check whether the MCP server you plan to build will expose local files, repo metadata, or external API access before using these examples.
- If you test the generated project, do it in a throwaway environment first and keep your own credentials/env vars unset.
Rated 2026-10-19 by an automated review of 6 files from the skill's repository.
Source
- Repository
- Jeffallan/claude-skills (all skills from this repository)
- Path
- skills/mcp-developer/SKILL.md
- Branch
- main
- Updated
- 2026-09-19
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