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

Annotations already cover safety (readOnlyHint, idempotentHint), and the description adds genuinely new operational context: the vendor endpoint is rate limited to 20 requests/minute. That is the kind of detail an agent needs to avoid throttling and is not present in any structured field. Return format and whether counters are cumulative vs. windowed remain unstated.

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?

Three short sentences, front-loaded with what is returned, followed by the scope exclusion and the rate limit. Every sentence carries distinct information and nothing is repeated from the title or schema.

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 zero-parameter, read-only utility with no output schema, the description covers purpose, scope boundary, and the main operational risk (rate limiting). It could go one step further by naming the sibling to use for actual scraping, but nothing essential to correct invocation is missing.

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 tool takes zero parameters, so there is nothing for the description to disambiguate and the baseline applies. The description correctly spends no words on parameter behavior and instead covers scope and limits.

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?

States a specific verb ('Read') and the exact resource (account credit, request and concurrency counters), which tells an agent precisely what comes back. The sentence 'Does not scrape a page' explicitly separates it from the three scraping siblings without requiring a schema comparison.

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 exclusion 'Does not scrape a page' combined with the usage-counter framing makes the intended use case (checking quota/credits before or instead of scraping) clear. It stops short of explicitly naming scrapeowl_scrape_page as the alternative for page fetching, so routing is inferred rather than stated.

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