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

Annotations already declare readOnlyHint and idempotentHint, and the description adds valuable behavioral context: start inclusive/end exclusive, UTC default, timezone conversion, and the response's period block for verification. However, it does not disclose whether this tool has row caps or pagination (implying a gap, since get_derivation explicitly avoids them).

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?

The description is front-loaded with the core purpose and uses short, information-dense sentences. Every paragraph adds value—timezone rules, inclusive/exclusive boundaries, and the sibling tool pointer—without fluff.

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?

Given the tool's complexity (timezone, exclusive end, alternative routing), the description is largely complete. It covers the main pitfalls and provides an output schema (so return format need not be explained). The missing aggregation parameter explanation and absence of pagination/row-cap info are minor gaps given the rich context provided.

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?

With 0% schema description coverage, the description must compensate. It thoroughly explains start, end, and tz semantics, but does not mention the 'aggregation' parameter at all. Zone is implied by 'bidding zone.' So it covers 3 of 5 parameters well but misses one entirely.

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 returns 'day-ahead clearing price for a bidding zone' with currency specifics, and distinguishes it from the sibling get_derivation for generation-weighted metrics. It names the specific resource and scope, making it easy to differentiate from other get_* tools.

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?

Explicitly says when to use an alternative: 'If you're computing a generation-weighted price metric... use get_derivation(slug="capture_price", …) instead.' Also provides detailed start/end semantics with examples and timezone handling, giving clear conditions for correct usage.

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