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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the bar is lower; the description still adds real value by making clear it only returns a command string rather than performing an installation, and that the command targets the current project. It does not state the return shape (bare string vs object), which is the remaining gap.

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?

One sentence, front-loaded with the verb and the artifact returned, with zero redundant clauses. Every element earns its place.

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 one-parameter, fully annotated, read-only helper this is essentially complete: what it returns, for which items, and where the command applies are all covered. The only omission is what the returned value looks like, and there is no output schema to fall back on.

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?

With a single parameter at 100% schema description coverage, the schema already documents the slug array, its item format and minItems. The description's 'one or more Facade items' reinforces plurality but adds no new syntax or constraint detail, so baseline 3 applies.

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?

States a specific verb ('Return') and a precise resource ('the shadcn CLI command that installs ... Facade items'), plus the scope ('into the current project'). It is clearly distinct from list_components, get_component and suggest_page, though it never names them to reinforce the contrast.

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?

Usage is only implied: an agent can infer you call this after choosing item slugs, but there is no explicit when-to-use, when-not-to-use, or pointer to the sibling that resolves a slug (get_component / list_components). Nothing misleading, but nothing guiding either.

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