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

Annotations already establish read-only, idempotent, non-destructive, open-world behavior, so the bar is lower. The description adds genuinely useful context beyond them: answers carry a confidence level and a source, and the agent is told to pass those on rather than assert rules as certain. It stops short of describing lookup failure modes or coverage limits.

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?

A single dense sentence front-loads the scope (passport + destination) and then lists the returned rule dimensions, followed by one short sentence on confidence/source. Nothing is wasted, though the list-heavy phrasing is slightly harder to scan than a clause-per-idea layout.

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 correctly carries the burden of describing what comes back — the rule dimensions plus the confidence/source fields — which is exactly the right content. It is nearly complete for a read-only lookup tool; only edge behavior (unknown passport/zone, partial coverage) is unaddressed.

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%, with enum values documented for plate and weight inside the schema, so the schema does the heavy lifting. The description adds only indirect meaning ('temporary vehicle import' maps loosely to plate/weight) and never clarifies the passport/destination code formats beyond what the schema states. Baseline 3 is correct.

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 the exact resource (entry rules for one passport + destination) and enumerates the dimensions returned: entry mode, stay length, day counting, visa-run reset, vehicle import. It implicitly separates itself from get_route_visa_rules (route-based) and get_vehicle_import_rules by scoping to a single passport/destination pair, though it never names those siblings explicitly.

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?

Usage is implied by 'one passport and destination', but there is no explicit when-to-use or when-to-prefer-a-sibling statement (e.g. vs get_route_visa_rules or get_vehicle_import_rules). The only directive is about relaying the confidence level and source to the caller, which is output-handling guidance rather than tool-selection guidance.

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