list_cities

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

Describes return format in detail (Dict with cities, each with name, code, coordinates, server_count). No annotations, but description covers behavior adequately for a read-only list tool.

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?

Extremely concise: one sentence plus structured Args/Returns. Every sentence adds value 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?

Fully complete for a simple list tool: input parameter fully explained, output format described, and sibling context clarifies scope. No gaps.

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 has 0% description coverage, but description adds meaning by specifying 'Two-letter country code' with examples (e.g., 'se', 'us', 'de'), adding significant value beyond schema.

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?

Description explicitly states 'List available cities for a given country', which clearly defines the verb and resource. It distinguishes from siblings like list_countries and list_servers.

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?

Specifies input as two-letter country code, but does not provide explicit 'when to use vs alternatives' guidance. Context from sibling tools makes it clear, but no explicit exclusions.

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