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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the description's job is extra context — and it delivers: it explains the exact eligibility flag, its origin in the owner's setting, and which fields come back. It doesn't state ordering or whether the directory is cached/refreshed, which keeps it off a 5.

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 the eligibility condition, then the return fields, then pagination. No filler; the parenthetical about "AI visibility" earns its place by tying the flag to something a user might say.

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 compensates by enumerating the returned fields (slug, name, city, country, menu URL), and it flags pagination. Only the pagination bounds and result ordering are left unspecified for a simple two-parameter read 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 two parameters and it only contributes the word "Paginated". It never mentions defaults (page 1, limit 20) or the limit ceiling of 50, which an agent needs to avoid over-requesting.

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 ("List restaurants") plus a precise scope: only those with directory_opt_in = 1. That distinguishes it from the sibling search_restaurants/get_restaurant by data scope, though it never names the alternative explicitly.

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 eligibility rule (owner opted into "AI visibility") is a useful selection criterion, but there is no explicit guidance on when to use this versus search_restaurants or get_restaurant_menu for finding a restaurant's menu. Usage is implied rather than stated.

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