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create-mcp-app

This skill should be used when the user asks to "create an MCP App", "add a UI to an MCP tool", "build an interactive MCP View", "scaffold an MCP App", or needs guidance on MCP Apps SDK patterns, UI-resource registration, MCP App lifecycle, or host integration. Provides comprehensive guidance for building MCP Apps with interactive UIs.

71

Quality

89%

Does it follow best practices?

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SKILL.md
Quality
Evals
Security

Quality

Content

93%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.

An excellent reference-style skill body: lean, highly executable, and well-structured with one-level-deep pointers to the SDK repo for details. Its only structural weakness is that guidance is spread across parallel sections rather than a single linear build workflow with explicit validation checkpoints.

DimensionReasoningScore

Conciseness

The body is dense with tables, commands, and code; it explains only MCP-Apps-specific facts (e.g. "MCP Apps HTML is served as an MCP resource with no same-origin server"), never general concepts Claude already knows. Every section earns its tokens, matching the lean-and-efficient anchor.

5 / 5

Actionability

Fully executable throughout: a copy-paste git clone with dynamic branch resolution, exact npm install lines for runtime and dev deps, an npm pkg set script command, concrete handler-registration code, and test commands with the SERVERS env var. Covers the common cases (new server, existing server, per-framework templates).

5 / 5

Workflow Clarity

The path from framework selection → reference-code retrieval → implementation notes → common mistakes → testing with basic-host is clearly sequenced, and the testing section provides a verification loop. Not 5 because the skill is organized as parallel reference sections rather than an explicit ordered workflow, and there are no validation checkpoints between build and serve (minor gaps).

4 / 5

Progressive Disclosure

No bundle files exist, and the SKILL.md appropriately keeps the body as a well-organized overview: a decision tree up front, compact file-level tables, and one-level-deep pointers into the cloned repo (/tmp/mcp-ext-apps examples, src/ API files, docs/patterns.md). Navigation is easy and nothing is inlined that belongs elsewhere.

5 / 5

Total

19

/

20

Passed

Description

81%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.

A strong description with excellent, naturally-phrased triggers and explicit use-when guidance. The main weakness is the capability statement itself: 'Provides comprehensive guidance' is an over-claim that names the domain without stating concrete actions.

Suggestions

Replace 'Provides comprehensive guidance for building MCP Apps with interactive UIs' with concrete capabilities, e.g. 'Builds interactive MCP Apps: registers a tool with _meta.ui.resourceUri, serves a bundled HTML resource, wires lifecycle handlers, and configures CSP for network requests'.

Avoid the over-claim word 'comprehensive' — state what the skill actually covers so the 'what' matches the specificity of the 'when' clause.

Consider mentioning key artifacts the skill helps produce (server.ts registration, vite-plugin-singlefile build) to sharpen distinctiveness from generic MCP-server skills.

DimensionReasoningScore

Specificity

The description names the MCP Apps domain and several relevant topics ("UI-resource registration, MCP App lifecycle, host integration"), but the capability statement is the generic "Provides comprehensive guidance for building MCP Apps with interactive UIs" — topics are noun phrases, not concrete actions like 'register a tool and resource' or 'configure CSP'. Not 4 because no specific executable capabilities are listed; not 2 because the domain topics go beyond a bare domain name.

3 / 5

Completeness

Both 'what' ("Provides comprehensive guidance for building MCP Apps with interactive UIs") and 'when' ("should be used when the user asks to...") are explicitly present, with concrete trigger phrases. Not 5 because the 'what' is vague — 'comprehensive guidance' does not state what the skill concretely does.

4 / 5

Trigger Term Quality

Quotes four natural user phrases verbatim ("create an MCP App", "add a UI to an MCP tool", "build an interactive MCP View", "scaffold an MCP App") plus needs-based triggers ("MCP Apps SDK patterns", "host integration"), covering App/View/UI synonyms comprehensively. This matches the top anchor for natural-term coverage.

5 / 5

Distinctiveness Conflict Risk

The MCP Apps niche is highly specific with distinct quoted trigger phrases; no realistic conflict with other skills' trigger conditions. Fits the 'clear niche with distinct triggers' anchor.

5 / 5

Total

17

/

20

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.

Validation — 16 / 16 Passed

Validation for skill structure

No warnings or errors.

Repository
modelcontextprotocol/ext-apps
Reviewed

Table of Contents

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