os_poi_nearest

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

Annotations already declare readOnlyHint, idempotentHint, and openWorldHint, so the read-only nature is covered. The description adds only the 'nearby' spatial behavior, matching the tool's name, but does not disclose ordering, default limit, or distance handling. 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?

A single, front-loaded sentence with no filler. It immediately states the action, resource, and input without wasting tokens.

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 is simple and has both annotations and an output schema, so safety and return structure are partially covered. However, the description omits crucial selection context, such as how maxDistanceMeters relates to 'nearby', whether limit has a default, and how this tool differs from the several similar nearest/search siblings.

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. It implicitly covers lat and lon but says nothing about the meaning, units, defaults, or effects of limit and maxDistanceMeters. The optional parameters are left unexplained beyond their schema types and constraints.

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 names a specific verb ('Find'), a specific resource ('OS Points of Interest'), and the input mode ('for a latitude/longitude point'). This makes it clearly distinguishable from sibling tools like os_poi_search (text-based search) and os_poi_within (area-based search).

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 the use case: call this when you have a lat/lon coordinate and want nearby POIs. However, it gives no explicit guidance about when not to use it or which alternatives (e.g., os_poi_search, os_poi_within, os_places_nearest) would be more appropriate.

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