get_route_performance

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

Annotations already declare read-only, idempotent, and non-destructive behavior. The description adds the notions of 'defensible' metrics and 'data-quality exclusions', which communicate that the output is reliability-focused and that some data points may be intentionally omitted. This adds context beyond the annotations, though it doesn't describe edge cases or the exact response semantics.

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 a single sentence that front-loads the primary output and scope. It is concise with zero wasted words, making it easy to parse quickly.

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?

Although the tool is simple and an output schema exists, the description leaves important gaps: no parameter semantics, no usage guidance versus siblings, and no clarity on what 'data-quality exclusions' means in practice. An agent would likely need to inspect the output schema or guess at parameter behavior to call this 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 description coverage is 0%, so the description must compensate, but it does not explain any parameters. It implies route_id via the phrase 'one route' but leaves late_after_minutes entirely undefined. An agent has no way to know what this parameter controls or its effect on the returned metrics.

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 uses a specific verb ('Return') and resource ('defensible lateness metrics and data-quality exclusions for one route'). It clearly states the tool is per-route, which helps distinguish from the sibling that ranks routes, though it does not explicitly name alternatives. It is not a tautology and avoids vague language.

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 guidance is given on when to use this tool versus rank_routes_by_lateness or get_route_trip_evidence. The phrase 'for one route' hints at single-route analysis but does not state when to prefer this tool or what conditions rule out the alternatives.

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