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

With no annotations, the description usefully declares 'Read-only' and the q >= 2 Latin-letter validation constraint. However, it does not describe what the returned objects contain (fields such as id/name needed to pass into target_cities), nor any rate or result-count behavior beyond what the schema's limit description implies.

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 the 'Read-only' safety marker, then mode rules, then downstream usage. Every clause carries operational information with zero padding.

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 small 3-param lookup with no output schema, the description covers safety, mode semantics, and intended consumption of results. The main gap is that the shape of the returned objects is only implied ('returned objects as target_cities'), not described.

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 coverage is 67% and q has no schema description at all; the description compensates by defining q's semantics (name search trigger, 2+ Latin letters). countries and limit are documented in the schema, and the description reinforces countries without repeating limit.

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 states a specific verb+resource (find main cities / name search of cities for given countries) and distinguishes its two modes by parameter. It does not name any alternative city-source sibling, but none of the sibling tools overlap, so the purpose is unambiguous.

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?

Explicit mode selection: no q returns main cities; q with at least 2 Latin letters performs a name search. It also gives workflow context by naming sdr_create_search / sdr_update_search as the downstream consumers, though it does not state exclusions or failure modes.

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