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

With no annotations, the description carries the burden of disclosure. It lists all output elements (countries, IDs, descriptions, freshness metadata, URLs) and notes 'FREE', indicating no cost. No contradictions or omissions for a read-only catalog.

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, no wasted words. Front-loaded with 'FREE' and 'Catalog of all usaref reference-data series', and each phrase adds essential information.

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?

Despite lacking an output schema, the description fully details what the tool returns. For a zero-parameter catalog tool with good annotation coverage, no additional context is needed.

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 input schema has no parameters, and description coverage is 100%. The description adds value by clarifying the tool's role as an initial discovery step, which is appropriate for a parameterless tool.

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: catalog all usaref reference-data series, including supported countries, IDs, descriptions, freshness metadata, and URLs. It also advises to call this first, distinguishing it from sibling tools like get_series which fetches a specific series.

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?

Explicitly instructs to call this first to discover existing data, providing clear usage context. While it doesn't list when not to use, the simplicity of a no-parameter catalog tool makes this guidance sufficient.

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