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

Annotations already declare readOnlyHint=true, openWorldHint=true, and destructiveHint=false, so the safety profile is covered. The description adds that the factor is 'precomputed' and 'documented,' hinting at its curated nature, but does not go deeper into response structure or pagination behavior—though the output schema likely handles that. It neither contradicts annotations nor adds substantial behavioral context beyond what structured fields provide.

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 action and resource, and zero filler. Every clause earns its place: the first defines what's returned, the second provides a usage constraint.

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 output schema and annotations cover return format and safety, the description is adequate for a read-only lookup tool. It clarifies the single-currency scope and the optional includes, and the 'documented factor value' framing distinguishes it from underlying-release tools. Slightly more detail on pagination or the nature of 'component scores' would elevate it, but not necessary.

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 100% and each parameter has a clear description (e.g., factor slug, ISO currency, date range, booleans). The description adds no parameter-level details beyond what the schema already states, so it meets the baseline without compensating for any gaps.

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 starts with a specific verb 'Return' and names the resource ('precomputed macro factor for one currency'), which clearly distinguishes it from the broader suite of sibling tools. It also clarifies the optional outputs (component scores and source references), leaving no ambiguity about what the tool delivers.

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 states when to use ('for a documented factor value') and when not to use ('not as a substitute for inspecting its underlying macro releases'). This gives clear direction without needing to name sibling tools, since the exclusion is behavioral rather than tool-specific.

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