get_purchasable_tiles

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

Annotations already indicate readOnlyHint=true. The description adds value by disclosing that tiles with luxury/strategic resources are listed first, and that it shows cost, terrain, and resources. No contradictions.

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?

The description is concise (6 lines) with a clear purpose statement followed by an Args section. Every sentence adds necessary information with no redundancy.

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's simplicity (1 param, no nested objects) and presence of an output schema, the description adequately covers purpose, parameter, and output details (cost, terrain, resources, ordering). Minor gap: no mention of potential empty results.

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 single parameter 'city_id' is described with 'City ID (from get_cities)', adding source context. Schema coverage is 0%, so the description compensates well by explaining the parameter's purpose and output characteristics.

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 purpose: 'List tiles a city can purchase with gold.' This is a specific verb-resource combination that distinguishes it from siblings like 'purchase_tile' and 'get_cities'.

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 implies usage (to see purchasable tiles for a city) but does not explicitly state when to use this tool versus alternatives. No exclusions or when-not-to-use guidance is provided.

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