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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, covering safety. The description adds behavioral context beyond annotations: 'it does not execute JavaScript or bypass access controls' and the cache/fresh semantics. This gives the agent a clear picture of side effects and limitations. No contradiction with annotations.

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, front-loaded with the core purpose, followed by clear usage constraints and parameter guidance. No wasted words; every sentence earns its place.

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 moderate complexity (checking multiple discovery files), the description covers the essential context: what it does, when to use it, limitations, and parameter guidance. An output schema exists, so return format description is not required. It could mention that coherence is evaluated only among 'declared' discovery files, but this is a minor gap.

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%: url is documented as an absolute public HTTP(S) URL with SSRF protections, and fresh has a default of false with a description. The description largely repeats these facts, though it phrases the fresh guidance more actionably ('Keep fresh=false to allow cache reuse'). Schema carries the semantic weight, so baseline 3 is appropriate.

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 opens with a specific verb and resource: 'Check declared robots, sitemap, feed, OpenAPI and llms.txt discovery coherence.' This clearly distinguishes it from sibling tools that check individual files (e.g., web.site.robots, web.site.sitemaps). The resource scope is well-defined.

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 gives explicit usage constraints: 'Use only for public HTTP(S) resources; it does not execute JavaScript or bypass access controls.' It also advises on the fresh flag: 'Keep fresh=false to allow cache reuse; set fresh=true only when a new upstream fetch is required.' However, it does not name alternative tools for single-resource checks, so it falls short of the highest bar.

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