Get fare zones for a stop

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

No annotations are provided, so the description must carry the behavioral burden. It describes a read operation ('Get') and adds useful context about Entur and ticket pricing, but it doesn't explicitly state that the operation is read-only, nor does it mention error handling, potential multiple zones, authentication requirements, or return format. For a simple lookup, this is acceptable but not rich.

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?

Two sentences with zero redundancy. The core purpose is front-loaded in the first sentence, followed by context in the second. No filler or repetition, making it efficient for an agent 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?

The tool has a single parameter and a clear purpose. The description explains what it does and why it matters (ticket price). It doesn't describe the output structure, which could be a gap since no output schema exists, but for a simple zone lookup this may be sufficient. It's complete enough for an agent to decide when to call it and what to expect conceptually.

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%—the schema fully documents stop_place_id with pattern, example, and source hint. The description adds no additional parameter details beyond what's in the schema, so the baseline 3 applies. It doesn't contribute extra semantic meaning about how the parameter relates to the result.

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 the verb 'Get' and resource 'fare zones', and adds context that these zones determine ticket prices. This uniquely identifies its function among siblings, which cover addresses, places, departures, and trips but none specifically for fare zones. The distinction is immediate and unambiguous.

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 implies when to use the tool: when needing fare zones for a stop. It doesn't explicitly name alternatives or exclusions, but given the sibling list, no other tool offers this capability, so an agent can infer correct usage. The added context about ticket price reinforces its purpose, but a more explicit routing statement would elevate it.

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