calculate_distanceCalculates the distance in kilometers between two Maidenhead locators to support geospatial logging and station proximity checks.
Calculates distance (km) between Maidenhead locators.
| Name | Required | Description | Default |
|---|---|---|---|
| end | Yes | ||
| start | Yes |
| Name | Required | Description | Default |
|---|---|---|---|
| result | Yes |
Changes observed during successful MCP inspections.
v1.1.4Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare this read-only, idempotent, non-destructive and closed-world, so the safety profile is fully covered by structured data. The description contributes one real fact beyond that – the result unit is kilometres – but says nothing about invalid-locator handling or failure behavior.
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?
A single front-loaded sentence with no filler; the unit is stated inline rather than tacked on. Nothing could be removed without losing information.
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?
With an output schema present and annotations covering safety and idempotency, the remaining burden is small: the description need only characterize the inputs. It does that at a high level but omits locator format and error behavior, the two things an agent is most likely to get wrong.
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 carry the parameters. 'Maidenhead locators' does establish the expected value type for both start and end, but it gives no format example (e.g. 'IO91wm'), no case or precision rules, and no way to tell which endpoint is which.
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?
States a specific verb (calculates) and resource (distance between two points) plus the unit (km). It implicitly separates itself from calculate_heading by naming 'distance', but never mentions that sibling explicitly, so an agent must infer the split.
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?
There is no 'use this when...' guidance, no exclusion of alternatives such as calculate_heading, and no statement of prerequisites. The only usable signal is the word 'distance', which requires inference.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.