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

Annotations already declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, and destructiveHint=false. The description adds meaningful behavioral disclosure beyond annotations: it does not execute JavaScript or bypass access controls, and it explains cache behavior with the fresh flag. This provides context that annotations do not cover.

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 concise sentences, front-loaded with the core purpose, followed by constraints and parameter guidance. Every sentence adds value; there is no fluff or repetition beyond reinforcing the schema, which is acceptable for emphasis.

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 the tool's moderate complexity, an output schema exists (covering return values), and annotations cover safety properties, the description is complete. It covers usage scope, constraints, and the freshness parameter. It could have explicitly mentioned that SSRF-sensitive destinations are rejected, but the schema already includes that, so it's not a gap in description 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 the baseline is 3. The description repeats the url requirement (absolute public HTTP(S) URL) and the fresh parameter semantics, but adds little beyond what the schema already documents. It reinforces key usage but doesn't introduce new semantic details beyond the 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?

The description clearly states the tool inspects hreflang, canonical, and declared-language coherence on a given URL. This specific verb+resource+scope distinguishes it from sibling tools like web.url.language or web.url.canonical, which focus on individual aspects rather than coherence.

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 explicitly restricts usage to public HTTP(S) resources and notes that it does not execute JavaScript or bypass access controls, giving clear exclusions. It also provides guidance on the fresh parameter (keep false for cache reuse, true only for new upstream fetch). It doesn't explicitly mention alternative tools, but the constraints and freshness instructions provide solid usage context.

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