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

Annotations already declare readOnlyHint=true and openWorldHint=false. The description adds useful context beyond annotations: daily updates, the reconciliation methodology, and the list of return fields. This provides transparency into what the score represents without contradicting annotations.

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 two sentences plus a concise 'Updates: daily' note. It front-loads the return value and usage guidance without any extraneous information. Every word earns its place.

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 description enumerates the return fields, gives clear usage context, and states update frequency. Since there is no output schema, the field list is useful. The optional history behavior is handled by the schema. Slightly more detail on the days parameter could be added, but overall it is complete for a read-only tool.

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?

The input schema covers 100% of the parameter description (the 'days' parameter has a detailed description in the schema). The tool description does not add any additional parameter semantics, so the baseline for high schema coverage 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 clearly states the tool returns a 0-100 EU-ETS carbon price pressure score with specific output fields and a CBAM proxy methodology. It uses a specific verb ('Returns') and resource, making it distinct from the many sibling 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?

The description explicitly enumerates user intents that should trigger this tool (EU carbon prices, CBAM tariff exposure, ETS compliance deficits, carbon border costs, timing contracts/hedges/escalators). It does not mention when not to use it or name alternative tools, but the clear use cases are sufficient.

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