Extract design tokens from website

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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, so the description is relieved of safety disclosure. It adds valuable behavior: 'using headless browser' implies the tool fetches the live page and could be subject to site access or latency, and 'get back the exact values' hints at the output precision. This goes beyond the annotations without contradicting them.

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 three sentences with zero fluff. It front-loads the primary purpose in the first sentence, then reinforces scope and integrates with siblings. Every sentence earns its place, making it concise and well-structured.

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?

The tool is simple (3 params, 1 required, booleans with defaults) and has no output schema, so the description need not detail return structure excessively. It covers the purpose, usage context, and practical behavior adequately. Minor gaps like error handling or return format are not critical given the simplicity and existing annotations.

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 input schema has 100% description coverage, so all three parameters (url, mobile, dark_mode) are already fully documented. The description adds no additional meaning about parameter usage or semantics, so it sits at the baseline of 3 as per the rubric.

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 'Extract' and a clear resource 'design tokens', enumerating the token categories (colors, typography, spacing, borders, shadows) and specifying it works on a live website via headless browser. This clearly distinguishes it from sibling search tools, which are about finding references, while this actually extracts values.

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 provides usage context by stating 'Give it any URL and get back the exact values used' and explicitly pairs it with search tools: 'find inspiration, then extract tokens from sites you like.' This implies a clear workflow, but it refers to 'search tools' generically without naming the specific sibling tools (e.g., design_search_styles), so it lacks the explicit alternative routing seen in the highest-scoring examples.

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