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

With no annotations, the description carries full responsibility for behavioral disclosure. It clearly states the tool always returns an empty list and the underlying reason (records carry no city field). While it does not mention side effects or permissions, none are expected for a read-only stub, so the transparency is adequate.

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, no filler, and the critical 'returns empty list' fact is front-loaded. The alternative guidance is brief and directly actionable.

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?

Given the tool has no parameters, no output schema, and a trivial behavior, the description covers everything an agent needs: it knows the result will be empty and that other tools should be used instead. Nothing essential is missing.

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, so the schema is empty and the description need not add parameter details. The baseline of 4 applies because there is no need to explain parameters; the description provides sufficient context about the tool's behavior.

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 clearly states the tool's function: it returns an empty list and explains why (no city field). It also distinguishes itself from siblings by explicitly pointing to alternatives ('narrow by near coordinates or by category instead'), so an agent immediately understands it is not the tool for city data.

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?

Explicitly tells the agent when not to use this tool and what to use instead: 'Narrow by near coordinates or by category instead.' This is direct usage guidance that prevents the agent from calling this tool expecting results.

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