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

With no annotations, the description carries full burden. It discloses that the tool fetches multiple pages, compares titles/word counts/previews, and requires 10 credits. It does not mention destructive actions or side effects, but the read-only nature is implied by 'fetch ... compare'. Adding idempotency or safety note would improve score.

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 sentence that efficiently conveys the core functionality, constraints (2-5 pages), and cost (10 credits). No unnecessary words or redundant information.

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 2 params, no output schema, and decent description, the tool is adequately explained. However, it could describe the output format (e.g., side-by-side table) or mention that results are read-only. The cost hint is useful, but missing output details slightly reduce completeness.

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?

Schema description coverage is 100%, so baseline is 3. The description adds context by stating urls should be 2-5 pages and api_key can be obtained via store_register, but the schema already covers these. No additional parameter details beyond schema.

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?

Description clearly states the action (fetch, compare), the resource (pages), and the specific items compared (titles, word counts, content previews). It also specifies the range of pages (2-5) and a cost (10 credits), making it distinct from sibling tools like web_fetch or web_search.

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 usage when you need to compare page details, but it provides no explicit guidance on when not to use it or mention alternatives. While the cost (10 credits) hints at a non-free operation, there is no comparative advice against other tools.

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