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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, openWorld). The description adds genuinely new behavioral facts: that the response includes the source of the value, and that the CEE17 campsite hook-up data is Europe-specific — a real geographic scope limit not visible in the annotations or schema.

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?

Front-loaded with the returned data types, which is the right ordering. The second sentence largely restates the first ('socket and plug types', 'mains voltage', 'campsite hook-ups'), so a small amount of redundancy keeps it from a 5.

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 values need no further explanation, and the read-only annotations carry the safety burden. With the required country_code, the locale behavior, and the Europe-only caveat all accounted for, an agent has everything needed to call this correctly.

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%, with both country_code (ISO 3166-1 alpha-2) and locale fully documented in-schema. The description only echoes 'one country', adding no format or syntax detail beyond the schema, so the baseline 3 applies.

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 precise resource set — IEC plug types A–N, mains voltage and frequency, value provenance, and the CEE17 campsite connector — scoped to 'one country'. No sibling tool touches plugs/voltage, so an agent can select this unambiguously from the tool list.

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 second sentence explicitly enumerates the query intents it serves (socket/plug types, adapters, mains voltage, campsite hook-ups), giving clear when-to-use context. It stops short of exclusions or naming an alternative, though no sibling overlaps this domain.

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