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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds substantive context beyond that: the authoritative source (Immigration Department), the side of the border measured (Hong Kong side), direction (leaving and entering), and the resident/visitor split. It does not discuss refresh cadence or data staleness, which would matter for a 'right now' tool.

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-loaded with the core purpose and efficient given the breadth of coverage. However, it is one sprawling sentence and the full enumeration of eight crossing names is a keyword-stuffing dump that could have been trimmed or moved.

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 explanation is not needed, and the description adequately frames the scope and data source. The main gap is the absence of any relationship to the plan_trip and service_updates siblings, which is the one thing an agent might still need.

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% and the single language parameter is fully documented with its enum values, so the schema does the heavy lifting. The description adds nothing about the language parameter, which is the correct baseline when the schema is complete.

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 (land and bridge crossings between Hong Kong and mainland China) and a specific measurement (current queue level and waiting range), enumerated by name across eight crossings. An agent can immediately tell this is a real-time status tool rather than a general travel planner.

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?

No explicit when-to-use guidance and no routing to alternatives. The closing phrase 'where to plan a trip to' gestures toward the plan_trip sibling but never names it or states the condition that would send the agent there, leaving the choice to inference.

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