CtrlK
BlogDocsLog inGet started
Tessl Logo

mcp-builder

Guide for creating high-quality MCP (Model Context Protocol) servers that enable LLMs to interact with external services through well-designed tools. Use when building MCP servers to integrate external APIs or services, whether in Python (FastMCP), Node/TypeScript (MCP SDK), or C#/.NET (Microsoft MCP SDK).

83

2.50x
Quality

Does it follow best practices?

Impact

100%

2.50x

Average score across 3 eval scenarios

SecuritybySnyk

Advisory

Suggest reviewing before use

SKILL.md
Quality
Evals
Security

Quality

Content

50%

Reviews the quality of instructions and guidance provided to agents. Good implementation is clear, handles edge cases, and produces reliable results.

A clearly structured four-phase guide with useful tables and concrete commands, but it loses points for redundant inline reference links, deferred (and missing) implementation examples, and a broken reference structure where none of the five linked detail files actually exist.

Suggestions

Fix the broken reference structure: the body links to `./reference/mcp_best_practices.md`, `node_mcp_server.md`, `python_mcp_server.md`, `microsoft_mcp_patterns.md`, and `evaluation.md`, but neither `./reference/` nor a populated `./references/` directory exists — either create these files or correct the paths so the signaled references resolve.

Add a complete, executable example MCP server inline (tool registration plus Zod/Pydantic input and output schemas) rather than deferring all implementation detail to the missing reference files.

Add explicit error-recovery feedback loops to the build/test phase (e.g., 'if `npm run build` or the Inspector reports errors, fix and re-run before proceeding') so the validation checkpoint is a real loop, not implicit.

DimensionReasoningScore

Conciseness

The body is well-organized with tables and bullets and avoids explaining concepts Claude already knows, but the 'Reference Files / Documentation Library' section restates links already given inline throughout the phases, adding redundant tokens that could be tightened.

2 / 3

Actionability

It offers some concrete guidance (fetch URLs, `npm run build`, `npx @modelcontextprotocol/inspector`, an XML output example), but the core tool-implementation detail is given as bulleted guidance ('Use Zod', 'Include constraints') with no complete executable server example inline, deferring real code to reference files.

2 / 3

Workflow Clarity

The four phases (Research, Implementation, Review/Test, Evaluations) are clearly sequenced with some checkpoints (build verification, answer verification), but explicit error-recovery feedback loops ('if build/validation fails, fix and re-run before proceeding') are implicit rather than spelled out.

2 / 3

Progressive Disclosure

The overview is well-signaled with one-level-deep reference links, but scored against the actual bundle: the body links to `./reference/*.md` (5 files) while no `./reference/` directory exists and `./references/` is empty — every referenced file is missing and the real `scripts/` bundle is never linked by path, breaking navigation.

2 / 3

Total

8

/

12

Passed

Description

100%

Based on the skill's description, can an agent find and select it at the right time? Clear, specific descriptions lead to better discovery.

A strong description that states concrete capabilities, includes an explicit 'Use when' trigger, and names specific frameworks across three languages; it closely follows the rubric's good-example pattern.

DimensionReasoningScore

Specificity

Names concrete actions ("creating high-quality MCP servers", "integrate external APIs or services") and three specific language/framework stacks (Python/FastMCP, Node/TypeScript MCP SDK, C#/.NET Microsoft MCP SDK), matching the 'lists multiple specific concrete actions' anchor.

3 / 3

Completeness

Explicitly answers both what ("Guide for creating high-quality MCP servers that enable LLMs to interact with external services through well-designed tools") and when via an explicit "Use when building MCP servers to integrate external APIs or services" clause, mirroring the top anchor.

3 / 3

Trigger Term Quality

Natural terms a user would say are well covered — "building MCP servers", "integrate external APIs or services", plus framework names (FastMCP, MCP SDK) users invoke when requesting this work.

3 / 3

Distinctiveness Conflict Risk

Clear niche (MCP server construction) with distinct, specific triggers and named frameworks, making it unlikely to fire for unrelated skills.

3 / 3

Total

12

/

12

Passed

Validation

93%

Checks the skill against the spec for correct structure and formatting. All validation checks must pass before discovery and implementation can be scored.

Validation15 / 16 Passed

Validation for skill structure

CriteriaDescriptionResult

relative_links

Relative link issues: 17 missing

Warning

Total

15

/

16

Passed

Repository
microsoft/agent-skills
Reviewed

Table of Contents

Is this your skill?

If you maintain this skill, you can claim it as your own. Once claimed, you can manage eval scenarios, bundle related skills, attach documentation or rules, and ensure cross-agent compatibility.