Server Quality Checklist

Tool Scores

• 21st_magic_component_refinerA
  3.8/5.0
  Behavior2/5

  Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

  No annotations provided, so the description must disclose behavioral traits. It states it 'returns redesigned version and instructions' but does not clarify whether the tool modifies files directly, requires write access, or has any side effects. The phrase 'improves UI' is ambiguous regarding automation level.

  Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

  Conciseness4/5

  Is the description appropriately sized, front-loaded, and free of redundancy?

  The description is concise, with two main clauses front-loading the usage condition and purpose. It wastes no words but could be slightly more structured (e.g., separating usage from behavior). Still, it is efficient for its length.

  Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

  Completeness3/5

  Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

  Without an output schema or annotations, the description partially covers the output (returns redesigned version and instructions) but lacks details on format or how the tool interacts with files. It adequately differentiates from sibling tools but leaves some behavioral gaps.

  Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

  Parameters3/5

  Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

  The input schema has 100% coverage with detailed descriptions for all three parameters. The tool description does not add extra semantics beyond the schema, so the baseline score of 3 is appropriate. The description's usage context does not directly elaborate on parameter usage.

  Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

  Purpose5/5

  Does the description clearly state what the tool does and how it differs from similar tools?

  The description explicitly states the tool refines/improves existing UI components, specifically React components or molecules (not big pages), and distinguishes it from building new components or inspiration. It uses specific verbs like 're-design/refine/improve' and names the resource clearly.

  Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

  Usage Guidelines5/5

  Does the description explain when to use this tool, when not to, or what alternatives exist?

  The description provides explicit guidance: 'Use this tool when the user requests to re-design/refine/improve current UI component with /ui or /21 commands'. It also clarifies it is for React components/molecules, excluding big pages, and implicitly contrasts with sibling tools like the builder (for new components).

  Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

• logo_searchA
  4.1/5.0
  Behavior3/5

  Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

  No annotations are provided, so the description carries the full burden. It discloses that the tool can return logos in different themes (light/dark) and multiple formats, implying no side effects. However, it does not mention error handling (e.g., if a logo is not found), authentication requirements, rate limits, or any destructive potential. The description is minimally adequate for a read-only search tool.

  Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

  Conciseness4/5

  Is the description appropriately sized, front-loaded, and free of redundancy?

  The description is well-structured with clear sections, bullet points, and examples, making it easy to scan. It is front-loaded with the core purpose and format options. While it is somewhat lengthy, every section provides useful information and no sentences are wasted.

  Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

  Completeness4/5

  Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

  Given the tool's simplicity (2 parameters, no output schema, no nested objects), the description is adequately complete. It covers input format, query examples, format options, and result components. It does not address pagination or errors, but for a single-return search tool, this is acceptable.

  Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

  Parameters4/5

  Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

  Schema coverage is 100%, with each parameter having a description. The tool description adds significant value by explaining the format enum (TSX = TypeScript React component, etc.), providing example query arrays, and detailing what each result includes (component name, code, import instructions). This goes beyond the schema to clarify usage.

  Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

  Purpose5/5

  Does the description clearly state what the tool does and how it differs from similar tools?

  The description clearly states the tool's purpose: 'Search and return logos in specified format (JSX, TSX, SVG).' It specifies the resource (logos) and the action (search/return). It distinguishes from sibling tools (component builder/inspiration/refiner) by focusing on logo retrieval rather than component creation or modification.

  Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

  Usage Guidelines4/5

  Does the description explain when to use this tool, when not to, or what alternatives exist?

  The description includes a dedicated 'When to use this tool' section with two specific scenarios ('/logo' command and missing local logos) and provides example queries. This gives clear context for invocation. However, it does not explicitly state when not to use this tool or mention alternative tools for other scenarios.

  Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

• 21st_magic_component_builderA
  4.2/5.0
  Behavior4/5

  Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

  With no annotations, the description carries full burden. It discloses the tool is read-only ('returns the text snippet') and requires agent follow-up. No side effects are mentioned, but the behavior is clear and no contradictions exist.

  Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

  Conciseness5/5

  Is the description appropriately sized, front-loaded, and free of redundancy?

  Three sentences, no wasted words. Front-loaded with usage context, then output nature, then required agent action. Every sentence serves a purpose.

  Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

  Completeness4/5

  Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

  Given 5 required parameters, no output schema, and no annotations, the description covers when to use, what it returns, and post-call actions. It omits output format details but the schema descriptions fill gaps. Adequately complete.

  Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

  Parameters3/5

  Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

  Schema coverage is 100% with detailed parameter descriptions. The description adds little beyond 'generate a search query' and 'formulate what component', which largely repeats schema content. Baseline 3 is appropriate.

  Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

  Purpose5/5

  Does the description clearly state what the tool does and how it differs from similar tools?

  The description explicitly states the tool's purpose: 'Use this tool when the user requests a new UI component' and gives examples like button, input, dialog. It clearly distinguishes from siblings by noting it 'ONLY returns the text snippet'.

  Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

  Usage Guidelines4/5

  Does the description explain when to use this tool, when not to, or what alternatives exist?

  The description clearly states when to use (when user requests a new UI component) and what the tool does not do (only returns snippet, agent must edit files). It lacks explicit exclusion of when not to use, but sibling tool names provide context.

  Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

• 21st_magic_component_inspirationA
  4.3/5.0
  Behavior4/5

  Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

  Given no annotations, the description carries the full burden. It clearly states the tool does not generate code, returns only text snippets, and requires follow-up integration. It does not disclose error handling or any destructive actions, but for a read-like operation this is adequate.

  Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

  Conciseness5/5

  Is the description appropriately sized, front-loaded, and free of redundancy?

  The description is extremely concise: three sentences that front-load the core purpose, clearly state the output, and give a usage directive. Every sentence earns its place with no redundancy.

  Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

  Completeness5/5

  Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

  Despite lacking an output schema, the description fully explains what the tool returns (JSON, text snippet) and provides a clear workflow expectation (must edit/add files after). Combined with the sibling tool context, it gives a complete picture for correct selection and invocation.

  Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

  Parameters3/5

  Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

  Schema coverage is 100%, so the schema already documents both parameters. The description adds no additional meaning beyond the schema; it merely references the tool's overall function. Baseline 3 is appropriate.

  Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

  Purpose5/5

  Does the description clearly state what the tool does and how it differs from similar tools?

  The description clearly states the tool's purpose: to fetch data and previews from 21st.dev, returning JSON/text of matching components without generating code. It explicitly positions the tool for inspiration and distinguishes it from sibling tools like the builder (which likely generates code).

  Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

  Usage Guidelines4/5

  Does the description explain when to use this tool, when not to, or what alternatives exist?

  The description advises using this tool when the user wants to see components or get inspiration, and notes that after calling, one must edit/add files to integrate the snippet. It implicitly contrasts with code generation tools, but does not explicitly state when not to use or name alternatives.

  Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.