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

With no annotations, the description carries the full burden and does real work: it discloses data provenance (port authority movement boards), per-row source attribution, TLS verification status, and the evidentiary nature of the data vs inference. It omits pagination/limit behavior, rate limits, and freshness caveats, which keeps it from a 5.

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 tight sentences, front-loaded with the resource and field list, then differentiation, then the call instruction. No filler, though the final sentence duplicates information the schema already carries for `query`.

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?

No output schema exists, and the description compensates by enumerating the returned row fields and provenance columns, plus disambiguating the data source. Missing pieces are the `limit`/pagination contract and how `imo`/`port` differ from `query`.

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 only 25%, and the description only addresses `query` (port name or 7-digit IMO). It leaves the separate `imo` and `port` properties undefined and their relationship to `query` ambiguous, and says nothing about `limit` — a real gap given how low coverage is.

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?

Opens with a specific verb+resource ("Berth-level vessel movements harvested from port authority movement boards") and enumerates the fields returned. It explicitly distinguishes itself from the AIS-inferred port_visits behind sibling tools, so an agent can route between them without opening a schema.

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?

States the lookup key ("Pass a port name or an IMO as `query`") and implicitly frames when to prefer this over AIS-inferred tools by calling the data "TESTIMONY from the port." It never names the concrete sibling alternatives (shipping_port, shipping_port_coverage) or states exclusions, so not a 5.

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