Server Quality Checklist

Tool Scores

• 21st_magic_component_inspirationA
  3.8/5.0
  Behavior3/5

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

  With no annotations, the description carries the full burden for behavioral disclosure. It states the tool only returns a text snippet, does not generate code, and requires manual integration afterward. However, it is internally inconsistent about 'previews' vs 'only returns the text snippet', and it does not mention no-match behavior, authentication, or data source limitations.

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

  Conciseness3/5

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

  The description is reasonably compact but contains redundancy: 'returns the JSON data' vs 'ONLY returns the text snippet' overlap, and the phrase 'or /21st fetch data' is awkward. The final sentence about post-call integration is valuable. Overall, it could be tightened without losing substance.

  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 lack of an output schema and annotations, the description covers the tool's purpose, return type, and required follow-up action. It misses a cleaner distinction between 'data/previews' and 'text snippet' and does not mention alternative tools by name, but it is still sufficiently complete for an agent to select and use the tool correctly.

  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 already provides 100% coverage with clear descriptions for both parameters. The description does not add additional parameter-level semantics beyond what the schema provides, so the baseline score of 3 applies.

  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 identifies the tool as a retrieval/inspiration tool for 21st.dev components, explicitly stating it returns JSON/text snippet data and does not generate code. This distinguishes it from sibling tools like the builder, which likely generates components.

  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 first sentence gives explicit triggers ('when the user wants to see component, get inspiration, or /21st fetch data'), and the phrase 'without generating new code' provides an exclusion for code-generation use cases. However, it does not name alternative sibling tools explicitly, so it stops short of a full when-not/alternative matrix.

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

• 21st_magic_component_refinerA
  4/5.0
  Behavior3/5

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

  With no annotations provided, the description carries the full burden of behavioral disclosure. It does mention that the tool returns a redesigned version and implementation instructions, which gives some output behavior. However, it does not disclose whether the tool modifies the file (write), requires specific permissions, or has any side effects. This ambiguity could mislead the agent about the tool's mutability.

  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 two sentences, front-loaded with an explicit usage directive, and every sentence earns its place. It is concise without redundancy, efficiently conveying purpose, usage, and output.

  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?

  The description covers the tool's purpose, when to use it, and what it returns (redesigned version + instructions), which is essential for a tool with no output schema. It leverages the schema's rich parameter descriptions. However, the lack of side-effect transparency and absence of annotations leave a small gap in complete understanding of the tool's behavior.

  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 description coverage is 100%, and each parameter has a detailed description, especially 'context' which explains what to extract and what to do if nothing specific is mentioned. Since the schema fully documents parameters, the description adds no extra semantics, but the schema already provides sufficient meaning.

  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 states a specific verb+resource: 'improves UI of components and returns redesigned version of the component and instructions on how to implement it.' It distinguishes from siblings by specifying it is for refining existing components (not building) and excludes big pages, which aligns with the tool name and differentiates it from 21st_magic_component_builder.

  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?

  It clearly says when to use: when the user requests to re-design/refine/improve a current UI component with /ui or /21 commands, or when context is about improving/refining a React component/molecule. It also excludes big pages. However, it does not explicitly name alternatives (e.g., 'use builder for new components'), so it lacks full explicit alternative guidance.

  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 appropriately carries the behavioral burden. It clearly discloses that the tool only returns a snippet and does not modify files, and it sets the post-call expectation to edit/add files. This is key behavioral context, though it omits details like failure modes or rate limits.

  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 three sentences, each serving a distinct purpose: when to use, what it returns, and the required follow-up. It is front-loaded with the trigger conditions and contains no fluff or redundant information.

  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?

  The description adequately covers the tool's purpose, output scope, and the agent's next steps, which is sufficient for selecting and invoking it. It could be improved by explicitly contrasting with sibling tools or describing the snippet's format, but the provided context satisfies the core requirements.

  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 description coverage is 100% (all five parameters have detailed descriptions). The tool description itself adds no parameter-specific meaning, but the baseline of 3 is sufficient because the schema already documents each parameter thoroughly, including concise search query constraints and extraction instructions.

  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 function: it returns a text snippet for a requested UI component. It provides specific trigger examples (e.g., '/ui', button, dialog) and explicitly notes the tool 'ONLY returns the text snippet', distinguishing it from sibling tools that likely handle inspiration or refinement.

  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 gives explicit when-to-use guidance with concrete examples of user requests. It also implies exclusions via 'ONLY returns the text snippet' and instructs that file integration must happen afterward. However, it does not explicitly name alternatives or state when not to use this tool.

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

• logo_searchA
  4.3/5.0
  Behavior3/5

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

  With no annotations, the description carries the full burden of behavioral disclosure. It explains return formats, themes, and result contents, but lacks information on error behavior, what happens if a logo isn't found, or any side effects. The mention of 'category filtering' is vague and not backed by schema parameters, adding confusion.

  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 well-organized with clear sections for usage triggers, examples, format options, and result contents. Every sentence adds value, and the structure makes it easy to scan. No unnecessary filler.

  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?

  For a 2-parameter search tool, the description covers purpose, usage, parameters, and results thoroughly. However, it omits error handling, any rate limits, and the meaning of 'category filtering' is not explained or reflected in the schema, leaving a minor gap in completeness.

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

  Parameters5/5

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

  Although schema coverage is 100%, the description adds substantial meaning: format options are explicitly defined (TSX/JSX/SVG with explanations), and queries are illustrated with multiple example styles (single, multiple, brand-specific, command-style, request-style). This goes well beyond the basic schema descriptions and greatly aids correct 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 formats. It distinguishes itself from sibling component tools by focusing specifically on logo retrieval with format options, multiple search support, and category filtering.

  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?

  Provides explicit when-to-use triggers (e.g., '/logo' command, adding a company logo not in the local project) and example query styles. However, it does not mention when not to use the tool or direct alternatives, so it falls short of a perfect 5.

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