anchorages

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

With no annotations provided, the description carries the full burden and does so excellently. It discloses the methodology ('No chart is consulted', 'reported "At anchor"'), the aggregation behavior, that outputs are extents rather than radii, that nothing is named, and the coverage caveat about unmonitored vessel traffic. These are meaningful behavioral traits beyond the schema.

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 structured into three focused paragraphs: core behavior, output geometry and naming limits, and coverage caveat. Every sentence earns its place, and the most important information is front-loaded. The example about eastern Singapore is illustrative without being verbose.

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?

Given the output schema exists, the description does not need to explain return fields and instead fills the semantic gaps: extent vs. radius, naming, and coverage interpretation. Input schema covers bbox/days/region, including the bbox-priority rule. An agent has enough to call this tool correctly and interpret results.

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 baseline is 3 and the description does not need to compensate. It does not add param-specific meaning beyond the schema, though the coverage caveat generally reinforces the role of the 'days' parameter in limiting how far back AIS reports are considered.

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 clearly states a specific resource and behavior: it finds where vessels actually anchor from recorded AIS positions, grouping touching 'At anchor' reports into single places. It also distinguishes itself from chart-based or permitted anchorages by saying it returns 'where ships really wait rather than where they are permitted to.' However, it does not explicitly name or contrast sibling tools, so it stops short of full sibling differentiation.

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 description gives clear contextual guidance, especially the line 'For a question about queueing, the first is the useful one,' which tells an agent when this tool's output is relevant. It also warns that absence from AIS data does not mean an anchorage is unused. It stops short of explicitly saying when to use this tool instead of siblings or naming alternatives.

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