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

With readOnlyHint and idempotentHint annotations already covering the safety profile, the description adds useful behavioral context: components are 'pre-adapted for the Sandpack preview environment' and the output is 'ready-to-use JS code with correct imports.' This goes beyond the annotations to clarify what the caller receives.

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?

Four short sentences, each earning its place: purpose and environment, component inventory, output guarantee, and usage guidance. The key differentiator ('Sandpack preview environment') is front-loaded, and there is no redundant or filler content.

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 simple read-only tool with one fully documented parameter and no output schema, the description is complete. It tells the agent exactly which components are available, what the returned code looks like, that it is pre-adapted for the target environment, and when to choose this tool over manual implementation.

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%, so the schema already fully documents the 'component' parameter, including the allowed values. The description restates the component list but does not add additional meaning, format details, or examples beyond what the schema provides. Baseline 3 is appropriate.

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 uses a specific verb ('Get') and identifies the exact resource ('shadcn/ui component code') with an explicit list of available components. It clearly differentiates from all sibling tools, none of which fetch component code, by adding the unique Sandpack adaptation detail.

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 final sentence provides explicit guidance: 'Use this instead of building complex UI primitives from scratch.' This clearly states when the tool is appropriate, though it does not enumerate when-not-to-use scenarios or name an alternative sibling tool, as no sibling overlaps with this functionality.

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