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

Annotations already declare readOnly and non-destructive with open-world access; the description adds genuinely useful behavior beyond that: the ten-source cap, restriction to public URLs, honest reporting of blocked/unreadable sources, and the explicit limitation that factual truth is not verified. It does not detail rate limits or per-source failure granularity, keeping it at 4.

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 tightly packed sentences, front-loaded with the core action and capped by the scope and disclaimer. Every clause carries information; nothing is redundant with the name or title.

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?

With no output schema, the description correctly supplies the return fields (status, final URL, title, quote match) and the failure semantics (blocked/unreadable reported honestly), which is everything an agent needs to call and interpret this single-parameter tool.

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 0%, so the description must carry the load, and it does: 'url' means public source URLs checked for HTTP responses, and 'quote' triggers optional quotation matching in fetched text, plus the max-of-ten constraint on the array. It omits URL format/length limits, so not quite a 5.

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 (check) and resource (public source URLs) with explicit scope (up to ten) and enumerates what is returned: HTTP success, final URLs, titles, and quote matches. This is clearly distinguishable from siblings like cleanread_read_page or tablelift_extract_tables.

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?

Gives a clear boundary in 'Does not verify factual truth' and notes it reports blocked/unreadable sources, which tells the agent how to interpret results. No sibling performs the same function, so no alternative-routing guidance is needed, but there is no explicit when-to-prefer-this statement.

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