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

Annotations already declare readOnly/optional/idempotent and closed-world, so safety is covered and the description is free to add output shape instead. It does that well, listing the ten comparison dimensions and the conditional match-score addition when home_country is passed — valuable since no output schema exists. It stops short of saying how missing or invalid country names are handled or how the match score is scaled.

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 purpose before the dimension list and the conditional behavior. The run-on dimension list is dense but each item signals a distinct returned field, so little is wasted; a bulleted or grouped form would read faster.

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 no output schema, the description carries the return-value burden and does so by enumerating the compared dimensions, which is the key thing an agent needs to decide whether to call it. Gaps are minor: response format/structure and the ambiguity around home_country (the schema marks it 'Required.' while the required array omits it, and the description treats it as optional) are left unresolved.

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 country_a/country_b are entirely undocumented in the schema — the description only implies they are the two compared countries. It does add real meaning for home_country (drives the MyNomadWorld match score) and hints at monthly_income_eur via 'tax for their income', but says nothing about current_country's role, leaving the under-documented half partly uncovered.

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 verb and resource ('Side-by-side comparison of two countries') and enumerates the compared dimensions, so the agent knows exactly what output shape to expect. It is also clearly separable from country_profile (single country) and recommend_countries (multi-country search) by the 'two countries' framing, and from digital_nomad_visas by covering visa as only one of ten dimensions.

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 'for someone deciding where to move' clause gives a clear usage context, and the home_country conditional ('With home_country it also gives each one's match score') implies when to supply that optional param. It never names a sibling as an alternative or states an exclusion, so the agent must infer that country_profile is the right pick for a single destination.

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