CBAM default value for a CN code and origin

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

Annotations already declare readOnly, idempotent and non-destructive, and the description adds substantial behavior beyond them: mark-up is not applied (a separate markup_rule quotes it), EU/Annex III origins return an explanation, unrecognised countries error, and Annex II/III content is deliberately excluded. That is richer disclosure than the safety hints alone.

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?

Purpose and scope are front-loaded, but the body is a single sprawling paragraph mixing return fields, exclusions, error behavior and legal citations. Every clause is informative, yet the run-on structure makes it harder to scan than it needs to be.

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?

There is no output schema, so the description carries the return-value burden and does so well: it enumerates direct, indirect and total embedded emissions, production-route letter, fallback values, and precursor handling. Combined with the coverage of error and exclusion cases, an agent has everything needed to call it correctly.

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 baseline is 3, but the description genuinely adds meaning about the country parameter: it accepts table names, common names, or ISO alpha-2 codes, unrecognised names error rather than fall back, and it names the special sentinel 'Other countries and territories'. This goes beyond the schema's examples.

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?

States a precise verb+resource pair: CBAM default values for goods under a CN code from a country of origin, and even names the authoritative source (the Commission's Excel). It implicitly separates itself from cbam_scope by noting that a code outside CBAM scope gets no value, but it never names siblings explicitly the way a 5 would.

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?

Gives concrete routing rules: unrecognised country is an error and never a fallback, third countries not listed should be queried as 'Other countries and territories', EU Member States and Annex III origins get an explanation instead of values, and electricity (2716) is out of scope. An agent knows exactly when this tool applies and what to do in edge cases.

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