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

Annotations already declare readOnly, idempotent, and closed-world, so the safety profile is covered. The description adds real context beyond them: results are limited to cities with actual listings and include a per-city count, which prevents the agent from treating this as a full gazetteer. It stops short of describing ordering or pagination, but the result set is inherently small.

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, front-loaded with what the tool returns and followed by the triggering condition. No redundant restatement of the title or annotations.

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 parameters and no output schema, the description carries the burden of describing the return value, and 'cities ... with how many' conveys a name-plus-count list adequately. It doesn't state the count's unit (groceries) explicitly or the ordering, a minor residual gap for a discovery 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?

Zero parameters, so the baseline is 4. The description correctly signals a no-argument call by framing it as a directory lookup with no filters.

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 the Saudi cities) plus a precise scope: only cities that have groceries in Dukkani's directory, and it returns counts. This is distinct from find_groceries (which searches within a city) and prepare_grocery_order without needing to open either schema.

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 two concrete invocation triggers: a city that isn't found and a user asking where the service works. That implicitly routes the agent away from find_groceries, but no sibling is named explicitly and there is no stated 'do not use for X' exclusion.

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