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mcp-schema-enum-regression

Keep generated MCP schemas strict-client compatible by avoiding nullable enum signatures.

35

Quality

31%

Does it follow best practices?

Impact

No eval scenarios have been run

SecuritybySnyk

Passed

No known issues

Optimize this skill with Tessl

npx tessl skill review --optimize ./.squad/skills/mcp-schema-enum-regression/SKILL.md
SKILL.md
Quality
Evals
Security

Quality

Content

22%

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

This skill identifies a real and specific problem (nullable enums in MCP schemas) but fails to provide actionable, executable guidance. It reads more like architectural notes or design principles than a skill Claude can follow step-by-step. The lack of any concrete code examples, validation commands, or sequenced workflow significantly limits its utility.

Suggestions

Add executable code examples showing how to detect nullable enum members in a schema (e.g., a C# snippet using ListToolsAsync and recursing schema nodes for enum arrays).

Add a concrete before/after example showing a problematic nullable enum signature and the corrected version.

Structure the Patterns section as a numbered workflow with explicit validation steps: 1) Run ListToolsAsync, 2) Check each enum node, 3) Fix nullable enums by converting to optional strings, 4) Re-validate.

Include the actual content or key snippets from the referenced files (McpToolGenerator.cs, regression tests) rather than just file paths.

DimensionReasoningScore

Conciseness

The content is reasonably efficient and avoids explaining basic concepts, but some bullet points are somewhat abstract and could be tightened. Phrases like 'Treat nullable enum parameters in MCP tool signatures as the hazard point' are descriptive rather than directly instructional.

2 / 3

Actionability

The skill provides no executable code, no concrete commands, and no copy-paste ready examples. The 'Examples' section only references file paths without showing actual code. The 'Patterns' section describes what to do abstractly but doesn't show how to do it with specific code or commands.

1 / 3

Workflow Clarity

There is no clear sequenced workflow. The patterns are listed as independent bullets without ordering, dependencies, or validation checkpoints. For a task involving code generation and schema validation, there should be explicit steps with verification (e.g., run ListToolsAsync, check output, fix, re-validate).

1 / 3

Progressive Disclosure

The content is organized into logical sections (Context, Patterns, Examples, Anti-Patterns) which is good structure. However, the referenced example files are not provided in any bundle, and there are no links to supporting documentation. The skill is short enough that no external files are strictly needed, but the file path references are unverifiable.

2 / 3

Total

6

/

12

Passed

Description

40%

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 targets a very specific technical niche (MCP schema nullable enum handling), which gives it strong distinctiveness but at the cost of completeness and trigger term coverage. It lacks a 'Use when...' clause, making it harder for Claude to know when to select this skill, and the single narrow action described limits its specificity score.

Suggestions

Add an explicit 'Use when...' clause, e.g., 'Use when generating or reviewing MCP tool definitions, JSON schemas for MCP servers, or when enum fields need to handle null values.'

Expand the 'what' portion to describe more concrete actions, e.g., 'Validates MCP tool schemas, rewrites nullable enum fields to use oneOf patterns, and ensures compatibility with strict-mode clients.'

Include natural trigger terms users might use, such as 'MCP tool definition', 'JSON schema', 'enum null error', 'strict mode', or 'schema validation'.

DimensionReasoningScore

Specificity

The description names a specific domain (MCP schemas) and a concrete action (avoiding nullable enum signatures), but it only describes one narrow action rather than listing multiple specific capabilities.

2 / 3

Completeness

The description answers 'what' (keep schemas strict-client compatible by avoiding nullable enum signatures) but has no explicit 'Use when...' clause or equivalent trigger guidance, which per the rubric caps completeness at 2, and the 'what' itself is quite narrow and lacks elaboration, pushing it to 1.

1 / 3

Trigger Term Quality

Includes some relevant technical terms like 'MCP schemas', 'nullable enum', and 'strict-client compatible', but these are fairly jargon-heavy. Users might say things like 'MCP tool definition', 'schema validation', or 'enum type error' which are not covered.

2 / 3

Distinctiveness Conflict Risk

This is a very narrow, specific niche — MCP schema generation with nullable enum constraints. It is unlikely to conflict with other skills due to its highly specialized focus.

3 / 3

Total

8

/

12

Passed

Validation

90%

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

Validation10 / 11 Passed

Validation for skill structure

CriteriaDescriptionResult

frontmatter_unknown_keys

Unknown frontmatter key(s) found; consider removing or moving to metadata

Warning

Total

10

/

11

Passed

Repository
sbroenne/mcp-server-excel
Reviewed

Table of Contents

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