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

Annotations already cover read-only/idempotent/non-open-world, and the description adds substantial context beyond them: the data is scraped from Knowledgebase country pages because no data file is published, the survey is biennial and the caveat names its year, it measures provision/infrastructure/skills rather than newcomer usability, and every response leads with a 'for information only' disclaimer. That is exactly the extra behavioral detail annotations cannot carry.

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-loaded with what the index measures, then scope, caveat, and parameter behavior in a dense but well-ordered passage. It is on the long side for a single paragraph, but nearly every clause adds distinct value; no obvious filler.

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?

With an output schema present, return values need not be explained, and the description still covers scope (41 countries), data provenance, survey cadence, semantic caveats, and parameter modes. Nothing an agent needs to invoke it correctly is missing.

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 coverage is 60%, and the description compensates well: it disambiguates `country` vs `countries`, explains the `index` enum values (egdi default; osi, tii, hci) and the `sort` default/override. Only `limit` is left unaddressed in prose, though its schema description already covers it.

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 (UN E-Government Development Index, 0–1) with its three named components and the reading scope (all 41 spine countries). An agent can distinguish this instantly from siblings like compare_countries or compare_connectivity, which handle different datasets.

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?

Explains the three usage modes clearly: single `country`, side-by-side `countries`, or a ranking by `index`, with default ordering (highest first) and the `sort=lowest` override. It does not, however, explicitly steer against any sibling or state exclusions such as when a broader country-comparison tool would be preferable.

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