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) or Node/TypeScript (MCP SDK).

81

1.60x
Quality

76%

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

62%

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

The body is a well-sequenced, actionable process guide with strong workflow clarity and validation checkpoints. Its main weaknesses are broken reference paths that don't match the bundle, a duplicated reference listing, and the absence of inline executable code examples.

Suggestions

Fix the reference paths so they match the actual bundle: the body links "./reference/mcp_best_practices.md", "./reference/python_mcp_server.md", "./reference/node_mcp_server.md", and "./reference/evaluation.md", but the bundle contains only "./scripts/" — align the links or add the referenced files.

Add at least one complete, executable inline tool-implementation example (a minimal @mcp.tool or server.registerTool function with input schema) so the guidance is copy-paste ready rather than deferred to references.

Remove the duplicate "Reference Files" section near the end (lines 287–329), which re-lists the same resources already cited inline, to tighten conciseness.

DimensionReasoningScore

Conciseness

The body is mostly high-signal (specific annotations, character limits, commands) and avoids re-explaining concepts Claude knows, but it is lengthy and repeats the reference-file listing in a duplicate "Reference Files" section that could be tightened; not a 3 because of this redundancy.

2 / 3

Actionability

Concrete commands appear ("python -m py_compile", "npm run build", "timeout 5s python server.py") and specific guidance is given (readOnlyHint, 25,000-token limits, Zod .strict()), but no complete executable tool-implementation code is inline — core examples are deferred to reference files, so it is not copy-paste ready.

2 / 3

Workflow Clarity

A clear four-phase sequence (Research → Implementation → Review/Refine → Evaluations) with numbered sub-steps and explicit validation checkpoints (syntax verification, build checks, a Quality Checklist), plus a Review-and-Refine feedback phase for error recovery.

3 / 3

Progressive Disclosure

References are well-signaled and one level deep, but the body links to "./reference/*.md" paths (mcp_best_practices.md, python_mcp_server.md, node_mcp_server.md, evaluation.md) that do not exist in the actual bundle, which is "./scripts/" — so the navigation is broken despite the structure.

2 / 3

Total

9

/

12

Passed

Description

90%

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 strong: it states a clear niche, concrete actions, and an explicit "Use when" trigger covering both Python and Node/TypeScript. It is only slightly held back by somewhat abstract action phrasing rather than enumerating multiple specific operations.

DimensionReasoningScore

Specificity

Names the domain and concrete actions ("creating high-quality MCP servers", "enable LLMs to interact with external services through well-designed tools", "integrate external APIs or services"), but the actions are somewhat abstract rather than a list of multiple specific concrete operations, so it falls short of a 3.

2 / 3

Completeness

Explicitly answers both "what" (creating high-quality MCP servers that enable LLMs to interact via tools) and "when" ("Use when building MCP servers to integrate external APIs or services"), with an explicit trigger clause.

3 / 3

Trigger Term Quality

Includes natural terms a user would say when needing this skill — "building MCP servers", "integrate external APIs or services", "Python (FastMCP)", "Node/TypeScript (MCP SDK)" — giving good coverage of common variations.

3 / 3

Distinctiveness Conflict Risk

MCP server development is a clear niche with distinct triggers (MCP, FastMCP, MCP SDK) unlikely to conflict with unrelated skills.

3 / 3

Total

11

/

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: 14 missing

Warning

Total

15

/

16

Passed

Repository
SynkraAI/aiox-core
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.