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

Annotations already declare readOnlyHint=true, openWorldHint=false, and idempotentHint=true, so safety is covered. The description adds useful return context: full markdown text, sources, and a citable derate.app URL. It does not mention auth or rate limits, but for a read-only lookup this is appropriate.

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 parallel bilingual sentences with the purpose front-loaded and no waste. The bilingual format is justified and efficient.

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 simple read-only retrieval with full schema coverage and annotations covering safety, the description explains the return format (full text, sources, citation URL) sufficiently for correct invocation. No output schema means the description appropriately carries that return-value context.

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 clear descriptions for both slug and lang. The description only reinforces that retrieval is 'by slug' and does not add meaning 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 states a specific resource ('one DERATE guide or news article') and retrieval mode ('by slug'), and the phrase 'one ... by slug' distinguishes it from list/search siblings. However, it does not explicitly name the alternative tool (search_guides) for sibling differentiation.

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 phrase 'by slug' implies a precondition, but there is no explicit when-to-use guidance or mention of the sibling search_guides for finding slugs. Usage is therefore implied rather than stated.

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