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

readOnlyHint and openWorldHint confirm it's a safe, non-network read, so the safety profile is covered. The description adds that the content concerns design/CSS context, but says nothing about what form the guide takes (prose, structured config, code examples) or its size, which matters for a pre-flight read.

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 compact sentence followed by a short imperative. Reasonably front-loaded and free of padding, though the first clause is a run-on list that could be tightened.

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 no-param documentation tool with readOnly annotations and no output schema, the description covers intent and the create_design prerequisite. It leaves the agent guessing about the guide's format and scope — e.g., whether it includes concrete CSS values or just conceptual naming — which matters for a tool whose sole output is its content.

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?

Zero parameters, so the baseline is 4. The description correctly signals the absence of inputs by framing this purely as reference material to consume rather than an operation with selectors or filters.

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 gestures at the content — card structure, fields/pictures templates can use, CSS variables and site parts — but never states a concrete verb like 'retrieves' or 'documents'. The title 'How to design a look' is vague, and the sibling create_design is only referenced as a prerequisite rather than contrasted.

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?

Explicitly instructs the agent to 'Read it before create_design', which gives a clear when-to-use condition tied to a named sibling. However, it doesn't explain when NOT to use it or what other discovery tools (find_pictures, list_topics) offer as alternatives.

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