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.
Scaffold a sep-NNNN.yaml requirement-traceability file for the MCP conformance repo from a SEP PR's spec diff.
OfficialCustom licenceAuto-check passed
Install New Sep
$ npx skills add modelcontextprotocol/conformance --skill new-sep -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install modelcontextprotocol/conformance new-sep --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/modelcontextprotocol/conformance.git skills-src && mkdir -p .claude/skills && cp -r skills-src/.claude/skills/new-sep .claude/skills/new-sep && 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 "new-sep" agent skill from https://github.com/modelcontextprotocol/conformance/tree/main/.claude/skills/new-sep into .claude/skills/new-sep/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "new-sep", 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/modelcontextprotocol/conformance/tree/main/.claude/skills/new-sepType 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 modelcontextprotocol/conformance --skill new-sep -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install modelcontextprotocol/conformance new-sep --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/modelcontextprotocol/conformance.git skills-src && mkdir -p .agents/skills && cp -r skills-src/.claude/skills/new-sep .agents/skills/new-sep && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "new-sep" agent skill from https://github.com/modelcontextprotocol/conformance/tree/main/.claude/skills/new-sep into .agents/skills/new-sep/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "new-sep", 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 modelcontextprotocol/conformance --skill new-sep -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install modelcontextprotocol/conformance new-sep --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/modelcontextprotocol/conformance.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/.claude/skills/new-sep .cursor/skills/new-sep && 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 "new-sep" agent skill from https://github.com/modelcontextprotocol/conformance/tree/main/.claude/skills/new-sep into .cursor/skills/new-sep/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "new-sep", 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/modelcontextprotocol/conformance.git --path .claude/skills/new-sep--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 modelcontextprotocol/conformance --skill new-sep -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install modelcontextprotocol/conformance new-sep --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/modelcontextprotocol/conformance.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/.claude/skills/new-sep .gemini/skills/new-sep && 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 "new-sep" agent skill from https://github.com/modelcontextprotocol/conformance/tree/main/.claude/skills/new-sep into .gemini/skills/new-sep/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "new-sep", 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 modelcontextprotocol/conformance new-sepInstalls 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 modelcontextprotocol/conformance --skill new-sep -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/modelcontextprotocol/conformance.git skills-src && mkdir -p .github/skills && cp -r skills-src/.claude/skills/new-sep .github/skills/new-sep && 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 "new-sep" agent skill from https://github.com/modelcontextprotocol/conformance/tree/main/.claude/skills/new-sep into .github/skills/new-sep/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "new-sep", 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 modelcontextprotocol/conformance --skill new-sep -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install modelcontextprotocol/conformance new-sep --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/modelcontextprotocol/conformance.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/.claude/skills/new-sep .opencode/skills/new-sep && 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 "new-sep" agent skill from https://github.com/modelcontextprotocol/conformance/tree/main/.claude/skills/new-sep into .opencode/skills/new-sep/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "new-sep", 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
new-sep- GitHub stars
- 129
- Token cost
- ~2.6k tokens
- SKILL.md length
- 1,307 words
- Files
- 1
- Skills in repo
- 3
- Repo updated
- First seen
- Licence
- Custom licence
At a glance
Scaffold a sep-NNNN.yaml requirement-traceability file for the MCP conformance repo from a SEP PR's spec diff.
- Works in 10 steps: Pre-flight checks → Parse arguments → Generate the skeleton → …
- SKILL.md covers Step 0: Pre-flight checks, Step 1: Parse arguments, Step 2: Generate the skeleton and Step 3: Fetch the spec diff, plus 6 more sections
- Calls gh, rg and jq; reaches modelcontextprotocol.io
What it does
New Sep is an agent skill from modelcontextprotocol/conformance, published by the product's own GitHub organization. Scaffold a sep-NNNN.yaml requirement-traceability file for the MCP conformance repo from a SEP PR's spec diff. Runs the new-sep CLI, then parses the modelcontextprotocol/modelcontextprotocol spec diff to populate requirements[] with the RFC 2119 sentences and proposed check IDs.
Its SKILL.md is about 2.6k tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.
It works with Model Context Protocol. The repository describes itself as: Conformance Tests for MCP.
Example prompts
- “/new-sep”
Requirements
- Node.js
Workflow steps
10 steps, taken from the step headings in SKILL.md.
- Pre-flight checks
- Parse arguments
- Generate the skeleton
- Fetch the spec diff
- Extract RFC 2119 requirements
- Map severity → check vs. excluded
- Confirm exclusions with the user
- Rewrite the YAML
- Suggest a host scenario
- Hand-off
What it can do on your machine
Read from SKILL.md and the folder at commit c37eec8. 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
Shell commands in SKILL.md call:
ghrgjqnpmnodenpx
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:
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.
Context cost
New Sep loads about 2.6k tokens when it runs. Until then it costs about 72 tokens; SKILL.md has 1,307 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
Its licence (Custom licence) doesn't allow us to republish the file, so here is its outline and opening line. It has 1,307 words (~2,645 tokens).
“You are bootstrapping a sep-NNNN.yaml file for a new SEP in the MCP conformance repo. The output is the requirement-traceability file specified by SEP-2484: a YAML that maps each normative sentence from the SEP's spec diff to a check: ID…”
- name
- new-sep
- argument-hint
- <sep-number>
Files
Just SKILL.md in .claude/skills/new-sep of modelcontextprotocol/conformance.
Open the folder on GitHubat commit c37eec8
Compare with similar skills
New Sep 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 |
|---|---|---|---|---|---|---|
| New Sep this skillmodelcontextprotocol/conformance | 129 | — | ~2.6k | Automated safety check: Pass | Custom licence | |
| MCP Server Builderanthropics/skills | 180k | 62 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 | 37k | 11 repos | ~3.1k | Automated safety check: Pass | Apache-2.0 | |
| Figma use_figma Plugin API Ruleswarpdotdev/warp | 65k | 4 repos | ~4.4k | Automated safety check: Pass | AGPL-3.0 | |
| Stitch to Remotion Walkthrough Videosgoogle-labs-code/stitch-skills | 8.4k | 6 repos | ~3.2k | Automated safety check: Notes | Apache-2.0 |
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Related
Works with
Questions about New Sep
What does New Sep do?
Scaffold a sep-NNNN.yaml requirement-traceability file for the MCP conformance repo from a SEP PR's spec diff. New Sep is an agent skill from modelcontextprotocol/conformance, published by the product's own GitHub organization.yaml requirement-traceability file for the MCP conformance repo from a SEP PR's spec diff.
How do I install New Sep in Claude Code?
Run `npx skills add modelcontextprotocol/conformance --skill new-sep -a claude-code`. Or copy the skill folder (.claude/skills/new-sep in modelcontextprotocol/conformance) into .claude/skills/new-sep in your project. Claude Code loads it when a task matches its description.
How do I install New Sep in Codex?
Run `npx skills add modelcontextprotocol/conformance --skill new-sep -a codex`. Or copy the skill folder (.claude/skills/new-sep in modelcontextprotocol/conformance) into .agents/skills/new-sep in your project. Codex loads it when a task matches its description.
Can I use New Sep 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 modelcontextprotocol/conformance --skill new-sep -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/new-sep, .gemini/skills/new-sep, .github/skills/new-sep and .opencode/skills/new-sep in your project.
What does New Sep need to run?
Going by SKILL.md and its folder, New Sep needs the command-line tools its instructions call (gh, rg, jq, npm, node and npx). Our summary lists: Node.js.
Does New Sep access the network?
SKILL.md names 1 domain. In commands or code: modelcontextprotocol.io; the agent is likely to contact it when it follows the instructions. This is read from the text; nothing was executed.
Is New Sep 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 New Sep use?
New Sep has a licence file (the repository's licence) that doesn't match a standard licence. Read it on GitHub before reusing the skill.
How many tokens does New Sep use?
About 2.6k tokens (SKILL.md is roughly 11k 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 New Sep?
Skills that share tags, products or a category with New Sep: 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, 37k stars) and Figma use_figma Plugin API Rules (warpdotdev/warp, 65k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains New Sep?
modelcontextprotocol (a GitHub organization, an official publisher) maintains it in modelcontextprotocol/conformance, which has 129 GitHub stars. The repository holds 3 skills in this directory. The repository was last updated on October 5, 2026.
Source: modelcontextprotocol/conformance on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.