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

Annotations already provide readOnlyHint=true and idempotentHint=true, covering the safety profile. The description adds behavioral detail beyond annotations: it returns 'other' stations (excluding the input one) and orders them nearest first.

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 two sentences with no wasted words. The first sentence front-loads the core function and ordering; the second provides targeted usage guidance.

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?

The core purpose and usage are clear, and annotations cover read-only/idempotent behavior. However, with no output schema and zero parameter documentation, the description leaves important operational details about limit and radius_km unstated, making it adequate but not complete.

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 carries the full burden of explaining parameters. It only vaguely references a radius and never names station_code, limit, or radius_km, nor explains units, defaults, or constraints. This is a significant gap.

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 states a specific behavior: returning other railway stations within a radius, ordered nearest first. It also distinguishes itself from the planner, which already does this internally, so an agent can tell it apart from siblings like plan_journey.

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?

It explicitly says when to use the tool (a place has no service of its own) and when not to (the planner already handles this internally; reach for it only when asked directly). This gives clear guidance on tool selection relative to alternatives.

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