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

Annotations already declare readOnlyHint=true and openWorldHint=false, establishing the safe read-only nature. The description adds behavioral context by listing the exact data fetched (source files, dependencies, registryDependencies, install command), which helps the agent anticipate the response. It does not contradict annotations and enriches beyond them, though it stops short of mentioning any edge cases or error behavior.

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 a single, front-loaded sentence that states the primary purpose and then lists the included details. It is dense but efficient, with no filler. It might be slightly long due to enumeration, but every clause adds value and the structure is clear.

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 single-parameter tool with no output schema, the description sufficiently explains what the tool returns and the scope (components and blocks). It covers the essential call details, so an agent can invoke it correctly without additional information. No critical gaps are apparent, though it could perhaps mention the exact format or any limitations.

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?

The schema has 100% description coverage and the parameter 'name' already includes examples ('button', 'data-table', 'pricing'). The tool description adds no additional semantic nuance about the parameter, so it does not exceed the baseline of 3 set by the schema-driven 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 uses a specific verb ('Fetch') and resource ('full detail for a single Cronus UI component or block by name'), then enumerates exactly what is returned (source files, dependencies, registryDependencies, install command). It also explicitly states it works for both components and blocks, which distinguishes it from siblings that list or search items without fetching full details.

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 implies the use case clearly: when you need full detail for a single named component or block. It states the tool covers both types, which provides context for selection. However, it does not explicitly mention when not to use it or point to alternatives (e.g., get_install_command), so it lacks explicit routing but still gives a clear context.

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