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

The annotations already establish read-only, idempotent, non-destructive behavior, so the description does not need to repeat that. It adds meaningful behavioral context beyond annotations by disclosing the optional API key mechanism and that a valid key selects Pro, plus the specific data sources and annualized percentage units. No contradiction with annotations.

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 short sentences with no filler or repetition. The core data content is front-loaded, and the API key note is cleanly separated. Every sentence earns its place.

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 rich annotations and the presence of an output schema, the description covers the core data scope, units, sources, and optional Pro authentication. It is slightly thin on parameter semantics and usage guidance, but the two parameters are enum-based and understandable enough for an agent to invoke 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 description coverage is 0%, and the description does not explain the `indicator` or `timeframe` parameters in any detail. It mentions the two Fed nowcasts in prose, which partially maps to the `indicator` enum, but it does not clarify how `timeframe` affects results or what the values mean beyond the enum names themselves.

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 identifies the resource and scope: US GDP growth, Atlanta Fed nowcast, and St. Louis Fed real GDP nowcast. It lacks an explicit action verb like 'retrieves' or 'provides,' so it is a noun phrase rather than a full statement, but the subject matter is unambiguous and distinguishable from the sibling forecast tools.

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?

No sentence explains when to use this tool versus the sibling forecast tools, and no alternatives are mentioned. Usage is only inferable from the tool name and the GDP content, not from any explicit guidance in the description.

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