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

With no annotations provided, the description carries full burden. It discloses the ranking order (cheapest first), the zone limit, and the currency-group behavior (EU ranked in EUR, US in USD, AU in AUD, GB in GBP). It does not mention edge cases like unavailable zones or errors, but the covered behaviors are meaningful.

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?

Four concise sentences, each providing distinct information: functionality, usage trigger, zone limit, and currency behavior. No redundancy or filler.

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 no output schema and no annotations, so the description provides the essential context: what it does, when to use, limits, and currency behavior. It could specify the return fields (e.g., price, rank, currency), but the core purpose is well covered.

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 both parameters. The description adds context about which currency group each region ranks in, but this is largely derivable from the currency enum. Overall, the description adds modest value beyond the schema.

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 tool compares current electricity spot prices across multiple zones and returns a ranked list cheapest first. The verb 'compare' and the specific resource 'electricity spot prices' distinguish it from sibling tools like compare_carbon or get_current_price.

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 explicitly provides a user query trigger ('which country has the cheapest electricity right now?') and states it is for comparing across regions. It also mentions the 10-zone limit, but does not explicitly state when not to use it or name alternatives like get_current_price for single-zone queries.

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