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build-mcp

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).

58

Quality

66%

Does it follow best practices?

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SecuritybySnyk

Low

Low-risk findings worth noting

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tessl review fix ./plugins/mcp/skills/build-mcp/SKILL.md
SKILL.md
Quality
Evals
Security

Quality

Content

42%Scale 1-3

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

This skill provides a comprehensive but overly verbose guide to MCP server development. Its strongest aspect is progressive disclosure—it effectively structures content across reference files with clear navigation. However, it suffers from significant verbosity (explaining concepts Claude already knows, repeating file references, and using filler phrases), lacks executable code examples in the main body, and has weak validation/feedback loops in its workflow.

Suggestions

Cut the content by 40-50%: remove explanations of basic concepts (DRY, error handling, what MCP is), eliminate repeated references to the same guide files, and trim filler phrases like 'Now that you have a comprehensive plan, begin implementation'.

Add at least one complete, executable code example in the main skill body (e.g., a minimal working MCP tool registration in Python or TypeScript) rather than deferring all code to reference files.

Add explicit feedback loops in Phase 3: 'If py_compile fails → fix syntax errors → re-run. If build fails → check TypeScript errors → fix → rebuild. Only proceed to Phase 4 when build succeeds with zero errors.'

Consolidate the Reference Files section at the end with the inline references throughout the phases—currently the same files are referenced 3-4 times each, wasting tokens.

DimensionReasoningScore

Conciseness

The skill is extremely verbose at ~300+ lines, with significant redundancy. It explains concepts Claude already knows (what MCP is, what error handling is, what DRY means), repeats references to the same guide files multiple times across sections, and includes unnecessary framing like 'Now that you have a comprehensive plan' and 'To ensure quality, review the code for'. The agent-centric design principles section, while useful, is padded with explanatory text that could be condensed to bullet points.

1 / 3

Actionability

The skill provides some concrete guidance (specific URLs to fetch, XML format for evaluations, tool annotation fields, specific commands like `python -m py_compile` and `npm run build`), but most of the content is procedural description rather than executable code. There are no complete working code examples in the main skill—those are deferred to reference files. The guidance is largely 'do X' without showing exactly how.

2 / 3

Workflow Clarity

The four-phase workflow is clearly sequenced and logically organized, but validation checkpoints are weak. Phase 3 mentions testing but the validation steps are vague ('review the code for...', 'verify Python syntax'). The warning about servers hanging is a good safety note, but there's no explicit feedback loop for fixing issues found during review—it's mostly a checklist without 'if X fails, do Y' recovery steps.

2 / 3

Progressive Disclosure

The skill effectively uses progressive disclosure with a clear overview in the main file and well-signaled one-level-deep references to language-specific guides, best practices, and evaluation guides. References are clearly labeled with emoji icons and descriptive summaries of what each file contains. The 'Reference Files' section at the end provides a clean navigation index.

3 / 3

Total

8

/

12

Passed

Description

89%Scale 1-3

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

This is a solid description that clearly identifies its niche (MCP server development) and includes an explicit 'Use when' clause with relevant technology-specific trigger terms. Its main weakness is that the 'what' portion could be more specific about the concrete actions the skill covers (e.g., defining tools, configuring transports, handling authentication) rather than staying at a high level.

Suggestions

Add more specific concrete actions to the 'what' portion, e.g., 'defining tools and resources, configuring transports, structuring server code, handling authentication' to improve specificity.

DimensionReasoningScore

Specificity

The description names the domain (MCP servers) and a general action ('creating high-quality MCP servers that enable LLMs to interact with external services through well-designed tools'), but does not list multiple specific concrete actions like defining tools, handling authentication, setting up transport layers, etc.

2 / 3

Completeness

Clearly answers both 'what' (creating high-quality MCP servers for LLM-service interaction) and 'when' ('Use when building MCP servers to integrate external APIs or services, whether in Python (FastMCP) or Node/TypeScript (MCP SDK)'). The explicit 'Use when' clause with specific triggers is present.

3 / 3

Trigger Term Quality

Includes strong natural trigger terms: 'MCP', 'Model Context Protocol', 'MCP servers', 'FastMCP', 'MCP SDK', 'external APIs', 'Python', 'Node', 'TypeScript'. These cover the main variations a user would naturally use when asking about building MCP servers.

3 / 3

Distinctiveness Conflict Risk

MCP server development is a very specific niche. The mention of FastMCP, MCP SDK, and Model Context Protocol makes this highly distinctive and unlikely to conflict with general coding, API, or LLM skills.

3 / 3

Total

11

/

12

Passed

Validation

100%

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

Validation11 / 11 Passed

Validation for skill structure

No warnings or errors.

Repository
NeoLabHQ/context-engineering-kit
Reviewed

Table of Contents

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