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

Annotations already mark the tool read-only, open-world, idempotent, and non-destructive. The description adds valuable behavioral context beyond those hints: it discloses that results carry confidence and source and tells the agent not to overstate rule certainty. This is meaningful and aligns with the open-world assumption.

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?

The description is compact, front-loaded with the core scope, and every clause earns its place by adding a meaningful rule category or output-handling instruction. No filler or repetition of schema information.

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 read-only lookup tool with no output schema, the description covers the essential output characteristics (confidence, source) and the rule scope. It does not describe pagination or error behavior, but annotations cover safety and the schema covers all parameters, so little critical information 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%, so the description does not need to compensate for undocumented parameters. It adds some context by mentioning 'temporary vehicle import', which ties to the optional plate and weight parameters, but does not add further input-parameter detail. Baseline 3 is appropriate.

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 names a specific verb-plus-resource ('Entry rules for one passport and destination') and enumerates the exact rule dimensions returned: entry mode, stay length, day counting, visa-run reset, and vehicle import. It is clear on its own but does not explicitly differentiate itself from sibling tools like get_route_visa_rules or get_vehicle_import_rules.

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 scope 'one passport and destination' implies when to use this tool versus a route-oriented sibling, but no explicit alternatives or when-not-to-use guidance is provided. The instruction to pass on confidence and source is a useful usage note for response handling, but it does not address sibling selection.

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