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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint=false, and destructiveHint=false, so the safety profile is covered. The description adds valuable context beyond that: the score composition (visa-free + visa-on-arrival + eTA), the comparison universe (~199 passports), name resolution in the breakdown, the public-domain data source, and a caveat to confirm entry rules with the destination authority.

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 core capability, then the omit-country mode, then provenance and a travel-safety caveat. Dense but every clause carries information; the long opening sentence is the only mild structural weakness.

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?

An output schema exists, so return-value detail is unnecessary. Combined with full annotation coverage and a 100% documented single parameter, the description supplies everything an agent needs: scope, the aggregate mode, score composition, data provenance, and a usage caveat.

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?

With 100% schema description coverage and only one optional parameter, the schema already documents the alpha-2 code format and the omit-for-league-table behavior. The description restates the same semantics (e.g., 'Omit country for the ranked league table') without adding 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?

States a specific resource (a country's passport) and concrete outputs: visa-free-access score, global rank, percentile, and a destination breakdown by access type. This is distinguishable from siblings like travel_advice or find_nomad_visas, which address different questions.

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?

Gives an explicit conditional usage rule: 'Omit country for the ranked league table,' which tells the agent how to get the aggregate view versus a single-country lookup. It does not name alternatives or exclusions, but the tool's scope is narrow enough that this is clear context rather than missing guidance.

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