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

Annotations already declare readOnly/idempotent/closed-world, so the safety profile is covered; the description goes further by disclosing the return scope (max 20 source links) and explicitly listing what is NOT returned (quotes, imagery, geometry, market series). That prevents the agent from requesting data this endpoint cannot supply.

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?

Two sentences, zero filler, with the core action front-loaded and the inclusion/exclusion lists packed into the second sentence. Every clause carries information an agent can act on.

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 takes on the burden of describing the payload and its limits, which it does well. It does not address behavior for a non-existent or unpublished slug, which is the only notable omission for a single-resource read.

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?

Only one parameter, and the schema already encodes its format via pattern and length constraints at 0% description coverage. The description adds the meaningful subtlety that the slug must reference a *published* facility, but no syntax or format detail beyond that.

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 and resource ('Read one published facility by slug') and enumerates the payload (canonical URL, sourced facts, verification date). It is clearly a single-entity lookup distinct from search_infrastructure, though it never names the siblings it differs from.

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?

'Read one published facility' and the 'by slug' phrasing imply a singular fetch rather than a search, which hints at when to prefer it over a search tool. However, no explicit when-to-use, when-not-to-use, or alternative tool is named, leaving the agent to infer the routing.

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