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 not explicitly state side effects, but as a read-only retrieval tool, the absence of mutation is implied. It discloses that it returns a checklist and rules, and mentions the default iconLibrary behavior and the need to ask the user, which adds useful behavioral context.

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 dense but well-structured, front-loading the most important instruction ('MANDATORY FIRST CALL'). Some sentences are long and combine multiple details, but every sentence contributes useful information. It could be broken into clearer paragraphs, but it's still efficient and not wasteful.

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?

Given there is no output schema, the description fully explains what the tool returns: a checklist, critical rules, patterns, and icon library specifics. It also covers the key workflow aspects (order, icon library selection, topic filtering) and connects to review_generated_code. This is arguably over-complete for a guidelines retrieval tool, leaving no obvious 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?

The schema already provides descriptions for both parameters, so the baseline is 3. The description adds extra value by explaining the iconLibrary default, naming supported values, advising to pass the same value to review_generated_code, and highlighting topic='patterns' for the generation checklist specifically. This goes beyond the schema's basic descriptions.

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 returns a step-by-step generation checklist, critical rules, component patterns, and icon library rules. It uses a specific verb ('get') and resource ('design guidelines'), and distinguishes itself from siblings like get_component_info and get_pattern by positioning itself as the mandatory first call.

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 explicitly says 'MANDATORY FIRST CALL before writing any @marmoui/ui code in this session,' providing strong when-to-use guidance. It also instructs to ask the user about icon library before writing code and to pass the same value to review_generated_code, offering clear workflow context.

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