21st_magic_component_inspiration

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

With no annotations, the description must fully disclose behavior. It does so by stating the tool returns JSON data and only a text snippet, does not generate code, and requires integration steps. This provides a clear behavioral profile, though it could have mentioned potential edge cases like no-matches or authentication, but for a straightforward fetch tool, the transparency is solid.

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

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

The description is three sentences, each earning its place: a usage trigger, a statement of return type, and a mandatory follow-up note. It is front-loaded with the primary use case and avoids fluff, making it highly concise and well-structured.

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

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

For a tool with two parameters, no output schema, and no annotations, the description covers all essential aspects: purpose, return format, and necessary post-actions. It is complete enough for an agent to invoke it correctly, though it could add a note on error handling or that the tool only applies to 21st.dev components, but these are minor gaps.

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

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

Schema description coverage is 100%, as both 'message' and 'searchQuery' have detailed descriptions including format constraints. The tool description adds no extra parameter semantics beyond what the schema already provides, so the score aligns with the baseline of 3 for high schema coverage.

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

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

The description clearly states the tool's purpose: it fetches and returns component snippets from 21st.dev when the user wants inspiration or a specific component. It distinguishes itself from siblings by explicitly stating 'without generating new code' and 'ONLY returns the text snippet,' making it clear this is a lookup tool, not a builder.

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

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

The description specifies when to use the tool ('when the user wants to see component, get inspiration, or /21st fetch data and previews') and provides a clear post-condition ('After calling this tool, you must edit or add files'). It does not explicitly name alternative tools or provide exclusion criteria, but the 'without generating new code' phrasing implies a contrast with the builder, offering adequate usage guidance.

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