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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the description adds value with the non-obvious caveat that 'some cities have no reviewed app offers.' It also flags the downstream dependency in 'Call first,' which goes beyond the structured 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?

Two compact sentences: the first states the exact resource and payload, the second adds both a data-quality caveat and ordering guidance. There is no redundant phrasing or filler.

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?

For a simple read-only list with no parameters and a provided output schema, the description supplies everything needed: the resource, the id requirement for downstream tools, and a relevant caveat about offer coverage. Nothing is missing for correct invocation.

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?

The tool has zero parameters and the schema completely covers the input contract. Since there is nothing to document, the baseline of 4 applies; the description appropriately focuses on output and usage rather than parameters.

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 names the resource ('editorial gateway cities'), the action ('List'), and the key payload ('their ids'). It distinguishes this from sibling tools like list_collections by specifying gateway cities and even notes that coverage varies.

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 says 'Call first' and explains that 'other tools need a destinationId from this list,' providing clear sequencing guidance. It does not enumerate alternatives or exclusion cases, but for a zero-parameter prerequisite list this is strong context.

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