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

Annotations already declare readOnly, idempotent, and non-destructive. The description adds valuable context: 'no auth required' and data source/licensing (IMF DataMapper, CC BY 4.0). This exceeds the annotation baseline by disclosing auth and licensing, though it omits potential rate limits or pagination details.

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 main purpose, then filtering options, and ending with source/licensing. Every sentence is informative and no filler.

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?

With an output schema present and annotations covering safety, the description fully covers metric, source, filtering, aggregates, auth, and licensing. Nothing critical is missing for correct invocation.

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% with parameter descriptions. The description adds semantic value by explaining the 'omit filters' behavior, inclusion of regional/income-group aggregates, and clarifying the 'countries' parameter as an alternative to 'country'. This goes beyond the schema definitions.

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 retrieves real GDP growth rate from the IMF WEO, specifying the metric and source. It distinguishes from siblings by emphasizing IMF and forward projections, making its purpose 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?

Provides clear usage context: filter by country codes and/or year range, or omit to get all countries plus aggregates. It implies when to use it but does not explicitly compare with alternatives like Eurostat or OECD GDP tools, though the IMF source and forward projections differentiate it.

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