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

Annotations already establish read-only, idempotent, non-destructive behavior, so the bar is lower. The description adds valuable context: licensing (CC BY 4.0), no upstream cost, ordering behavior (relevance default, population, elevation, Wikipedia), and multilingual lookup support. This goes beyond annotations without contradicting them.

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 moderately long but every sentence adds value: scope, filtering, result fields, ordering, language support, and licensing. It is front-loaded with the primary purpose, then systematically covers parameters and output. No filler or 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?

For a 9-parameter search tool with a rich schema and output schema, the description covers all essential behavioral aspects: search scope, filtering options, ordering, result fields, language support, and licensing. Pagination is handled by schema parameters (start_row, max_rows). The agent has everything needed to select and call the tool correctly.

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 100%, so baseline is 3. The description restates parameter meanings (e.g., feature class codes, feature code examples, order_by options) that are already in the schema, adding little new information. It does not compensate for any schema gaps because none exist; it merely reinforces what the schema states.

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 ('Search') and resource ('GeoNames geographical database'), enumerates the types of features covered (places, populated areas, mountains, rivers, 12M+ features), and clarifies global scope. This clearly distinguishes it from sibling geocoding tools like nominatim.geocode.search or geo.places.search, even without naming them.

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 explains what the tool does and lists filtering options, but it does not explicitly state when to use this tool over alternative geocoding or place-search tools. No conditions, exclusions, or sibling comparisons are provided, leaving the agent to infer usage from the domain.

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