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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so safety is covered. The description adds genuine scope context beyond them: the 500 m radius for monuments, that this is a point-in-Ireland lookup, and which data providers (GeoHive, SMR, NPWS) are consulted. It stops short of noting rate limits, latency, or partial-coverage behavior for points outside Ireland's datasets.

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, front-loaded with the operation condition ('For a WGS84 point in Ireland'), with no filler. The first sentence is a dense enumeration that is long but each item earns its place; the second sentence cleanly handles the exclusion and hand-off.

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?

An output schema exists, so return-format explanation is not required, and the description still supplies everything else an agent needs: coordinate system, country scope, the full set of returned sections, spatial limits, and explicit out-of-scope topics with an alternative. Nothing needed to call this correctly is missing.

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%, so the schema already documents lat, lon, hours and max_tokens, making 3 the baseline. The description adds marginal meaning only — the 500 m monument radius and the notion that forecast hours feed the Met Éireann station result — but does not explain the interaction between max_tokens and the breadth of returned sections.

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 (returns what is at a point) and enumerates the exact resources returned: county, local authority, constituency, electoral division, small area, settlement, nearest Met Éireann station/forecast, SMR monuments within 500 m, and NPWS protected sites. It also names the sibling (ireland_call) that covers the excluded data, so an agent can distinguish it without opening another schema.

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 gives an explicit negative condition — 'Not live observations, river levels, buoys, bikes or populations' — and routes those cases to ireland_call by name. That covers both the when-not and a concrete alternative, which is the strongest form of routing guidance.

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