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

Annotations already declare this as a read-only, idempotent, non-destructive, non-open-world operation. The description adds useful context about the price source and that the default behavior is 'latest published.' It does not discuss authentication, rate limits, or return format, so it adds moderate value beyond 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 a single, front-loaded sentence with no wasted text. It communicates the core action, freshness, source, and authority efficiently.

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 price-fetching tool with rich annotations and a fully documented schema, the description is largely sufficient. It could mention the historical option or return value shape, but the schema covers the parameter and the purpose is clear.

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 100%, so the single parameter 'all' is already fully documented as retrieving the complete historical price series. The description does not elaborate on parameter behavior beyond implying the default is latest-only, which is adequate but not additive given 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 verb and resource: get the latest published CBAM certificate price. It also names the underlying source, EEX EU ETS auction averages, which makes the purpose concrete. It does not explicitly distinguish itself from sibling tools, but the price-specific purpose is clear from the resource named.

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 does not explain when to use this tool versus alternatives such as cbam_status or cbam_changes. It implies usage by saying 'latest published,' but gives no explicit when-to-use or when-not-to-use guidance.

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