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

Annotations already declare this read-only, idempotent, open-world and non-destructive. The description adds genuinely useful context beyond them: the underlying dataset, the flash-estimate caveat for the newest month, and a 1-credit cost. It says nothing about return shape or units beyond '% change', which is a gap given there is no output schema.

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?

Front-loads the metric definition, then audience, then source, then coverage caveats and cost. Dense and information-bearing throughout; no filler sentences to cut.

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 two-parameter read-only indicator lookup with no output schema, the description covers metric definition, source, geographic limits, flash-estimate behavior, and cost. Only the returned series format (e.g., month labels, value precision) is left unstated, which is a minor omission.

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 both `geo` (codes, EU27_2020/EA variants, no UK) and `n` (1-100, default 12) are already documented. The description reinforces geo semantics ('one European country or the EU / euro area') but adds no format or edge-case detail beyond the schema, so 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?

Names the exact metric (HICP all-items annual % change), the geography, the Eurostat dataset (prc_hicp_minr), and the year-over-year definition. An agent can distinguish it from siblings like eu_gdp_growth or eu_unemployment_rate without opening a schema.

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 concrete usage framing ('what is inflation in Germany right now') and explicit coverage boundaries: EU/EFTA/candidate countries, not the UK or the US. It does not explicitly route to alternative siblings (e.g., national CPI tools), but the scope constraints give clear when-to-use/when-not-to-use signals.

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