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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered. The description adds value by stating native currency and resolution of returned data, plus the need to connect an account. It does not contradict annotations and provides useful behavioral context.

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 with no filler. The core purpose is front-loaded, and the account requirement is added succinctly. Every word contributes.

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?

For a read-only tool with four params (one required), annotations cover safety, and schema provides defaults for to/from. The description covers purpose, return characteristics, and a prerequisite. It does not mention behavior when no account is connected or invalid zone handling, but these are minor gaps given the annotations and schema.

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 coverage is 75% with descriptions for to, from, and zone; resolution lacks a description. The description does not elaborate on any parameter beyond what the schema provides, so it adds minimal semantic value. Baseline 3 is appropriate given high schema coverage.

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?

Description states specific verb 'get' and resource 'day-ahead electricity prices', with scope per zone. It distinguishes from get_realtime_prices by specifying day-ahead and native market resolution. Clear and unambiguous.

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?

Implied usage via 'day-ahead' and the account requirement, but no explicit guidance on when to use this vs siblings like get_realtime_prices or get_forecast. It does not name alternatives or exclusion conditions.

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