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

Beyond the readOnlyHint/idempotentHint annotations, the description discloses meaningful behavioral context: the data source (open ilyankou/passport-index-dataset, public domain), the approximate scope (~199 passports), and the access-type composition (visa-free + visa-on-arrival + eTA). The practical caveat to 'confirm entry rules with the destination authority before travel' adds responsible usage context. No contradiction with the annotations.

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?

Three sentences with zero waste: the first front-loads the core function and its outputs, the second gives the optional-parameter mode, and the third covers provenance and a safety caveat. Every sentence earns its place.

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 single-optional-parameter, read-only tool with an output schema and safety annotations, the description covers purpose, output contents, dual-mode usage, data provenance, and a travel-safety precaution. 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 description coverage is 100% — the 'country' parameter is already documented with alpha-2 format examples and the omit-for-league-table behavior. The description restates this same omit behavior rather than adding new parameter semantics, so the baseline of 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?

The description states a specific verb ('returns') and resource (a country's passport visa-free-access data), then enumerates the exact outputs: visa-free-access score, global rank, percentile among ~199 passports, and full destination breakdown by access type. It is clearly distinguishable from all 25 siblings, none of which cover passport or visa topics.

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 description gives clear invocation context with two modes: 'for a given country's passport' and 'Omit country for the ranked league table.' It provides a conditional usage rule but does not explicitly name alternatives or state when-not-to-use; however, the tool's domain is so distinct from its siblings that the intended use case is unambiguous.

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