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

Annotations already declare this a safe, idempotent read (readOnlyHint, idempotentHint, destructiveHint=false), so the description earns credit for what they don't cover: the exact source dataset (Eurostat gov_10q_ggdebt), the Maastricht consolidated definition, and the caveat that quarterly ratios differ from annual EU deficit-procedure figures. The stated 1-credit cost is also useful operational context.

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?

Well front-loaded: the metric, geography, and units come first, followed by the use-case framing, source, and caveat. The audience phrase ('for investors, students and reporters') is mild padding but does convey the question shape the tool answers.

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 simple three-parameter read with no output schema, the description supplies source, definition, units, and the key interpretation caveat, which is enough to call it correctly and interpret the number. It doesn't say what the response actually looks like (a single value or a series of n quarters), a minor remaining gap.

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%, so geo codes, the n range, and the PC_GDP/MIO_EUR units are already fully documented in structured fields. The description restates the default unit but adds no syntax or format detail beyond the schema, so the baseline 3 applies.

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?

States a specific resource (general government gross debt), scope (one European country, quarterly), and both output units with the default called out. An agent can distinguish this from eu_government_deficit or eu_gdp_growth on the face of the description alone.

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 example questions ('how big is Greece's or Italy's national debt') give implied usage context, and the note about quarterly vs annual figures in EU deficit procedures hints at the boundary with deficit tools. But it never names an alternative sibling or states a when-not-to-use condition, so an agent must infer routing.

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