Ferry port live board

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

Annotations already declare readOnlyHint and openWorldHint, so safety is covered. The description usefully adds that the board is for today only, that statuses include cancellation with a reason, and that coverage is limited to roughly 25 ports. It does not discuss rate limits or auth, but those are lower-priority for this read-only 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?

The description is front-loaded with what the board returns, then coverage limits, then the concrete example. It is efficient, though the parenthetical port list and example are somewhat verbose for an agent that already receives rich schema descriptions.

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, two-parameter tool with no output schema, the description explains what data comes back, the temporal scope, status semantics, and the key coverage caveat that routes agents to ferry_timetable. Nothing essential is missing for correct invocation.

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 coverage is 100% and already documents both port and limit, including examples and the default limit of 40. The description adds a usage example for port but does not add meaningfully new semantics beyond the schema, so the baseline of 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?

States a specific verb and resource (live departures and arrivals for a ferry port today) and enumerates the returned fields: scheduled, estimated and actual times, vessel, and status including cancellation reason. It explicitly distinguishes itself from ferry_timetable for ports without a live board.

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?

Provides an explicit when-to-use boundary: about 25 ports have a board, and ferry_timetable should be used for the others. It also gives a concrete example (port "小琉球"), leaving little ambiguity for an agent selecting between the two ferry tools.

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