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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) or Node/TypeScript (MCP SDK).

80

1.60x
Quality

75%

Does it follow best practices?

Impact

88%

1.60x

Average score across 3 eval scenarios

SecuritybySnyk

Low

Low-risk findings worth noting

Fix and improve this skill with Tessl

tessl review fix ./.claude/skills/mcp-builder/SKILL.md
SKILL.md
Quality
Evals
Security

Quality

Content

63%Weight 40%Scale 1-5

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

The content is a well-structured, actionable four-phase guide with concrete commands and validation steps, but it is somewhat redundant and its progressive-disclosure references point to a ./reference/ directory that is absent from the bundle.

Suggestions

Remove the duplicated 'Reference Files / Documentation Library' section at the end; the per-phase inline citations already cover each file and would save meaningful tokens.

Create the referenced ./reference/ directory (mcp_best_practices.md, python_mcp_server.md, node_mcp_server.md, evaluation.md) or repoint links to the existing scripts/evaluation.py and scripts/example_evaluation.xml so progressive disclosure resolves to real files.

Add at least one minimal inline executable MCP server skeleton (Python FastMCP and TypeScript registerTool) in SKILL.md so the core build is copy-paste ready without requiring the missing reference files.

DimensionReasoningScore

Conciseness

Mostly directive bullets rather than concept over-explanation, but the ~323-line body repeats the reference link library at the end (Phase 1/2 already cite each file) and several principles in 1.1 restate widely-known agent design ideas, so it could be tightened.

3 / 5

Actionability

Provides concrete commands (python -m py_compile, npm run build, timeout 5s python server.py), specific WebFetch URLs, and explicit tool annotations, but defers most executable server code to reference files rather than showing inline scaffolding.

4 / 5

Workflow Clarity

A clear four-phase sequence with validation checkpoints in Phase 3 (test/build, quality checklist) and safe-testing guidance; minor gaps as Phase 3.1 review is a checklist rather than an explicit validate-fix-retry loop in the main flow.

4 / 5

Progressive Disclosure

The body is well-signaled with one-level-deep ./reference/*.md links, but those referenced files (mcp_best_practices.md, python_mcp_server.md, node_mcp_server.md, evaluation.md) do not exist in the bundle — only scripts/ exists — so the disclosure structure is broken against the actual bundle.

3 / 5

Total

14

/

20

Passed

Description

87%Weight 40%Scale 1-5

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

The description is well-crafted: it states a concrete capability and provides an explicit, natural-language trigger clause with framework-specific anchoring. It is concise, in third person, and clearly distinguishable from other skills.

DimensionReasoningScore

Specificity

Names the MCP domain plus several concrete actions ('creating high-quality MCP servers', 'enable LLMs to interact with external services through well-designed tools', 'integrate external APIs or services'), with minor coverage gaps versus the comprehensive 5-anchor list.

4 / 5

Completeness

Explicitly answers both 'what' (guide for creating high-quality MCP servers) and 'when' with a concrete 'Use when building MCP servers to integrate external APIs or services' clause.

5 / 5

Trigger Term Quality

Includes natural trigger phrases ('building MCP servers', 'integrate external APIs or services') and concrete framework keywords (FastMCP, MCP SDK), though a few common synonyms are missing.

4 / 5

Distinctiveness Conflict Risk

Occupies a clear niche (MCP servers) with distinct triggers and framework/language specificity (FastMCP, Node/TypeScript MCP SDK), giving minimal conflict risk with other skills.

5 / 5

Total

18

/

20

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: 14 missing

Warning

Total

15

/

16

Passed

Repository
SynkraAI/aiox-core
Reviewed

Table of Contents

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