passage_time

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

With no annotations provided, the description carries full behavioral burden and does so thoroughly. It discloses the data source ('recorded tracks'), sample-size limitations ('Below five observed passages no median is given at all'), the always-relevant spread, and boundary conditions such as excluding waiting time at origin and excluding mid-voyage records.

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 definition is front-loaded with a clear one-sentence summary and every caveat is decision-relevant. Slight redundancy exists ('This is measured from recorded tracks' restates the first sentence) and the 'fourteen hours' example is illustrative but could be tightened without losing meaning.

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 tool with no annotations, the description is remarkably complete: it explains measurement methodology, statistical presentation, minimum sample size, and edge cases. Since an output schema exists, the lack of explicit return-value description is not a gap. An agent can invoke this tool and interpret its result correctly.

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%, so the baseline is 3. The description adds meaningful semantic detail beyond the schema by defining when the clock starts for origin/destination and what counts as a valid passage, but it adds little about the `days` parameter beyond what the schema already states.

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 first sentence, 'How long this leg actually takes, from ships that made it,' states precisely what the tool computes and the empirical source. It also distinguishes itself from a speed-based estimate ('Not distance divided by an assumed speed'), which separates it from sibling tools that might provide traffic or congestion data.

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 makes clear this is the tool to use when actual measured passage durations are needed, and explicitly rules out the speed/distance alternative. It does not name sibling tools or state explicit when-not-to-use conditions, but the context is strong enough for an agent to select it appropriately.

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