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

With no annotations provided, the description carries the burden of behavioral disclosure. It discloses the core behavior: searching by code or description, finding the 8-digit code, and determining CBAM status and sector. However, it does not mention return format, error handling, pagination, or rate limits, leaving some gaps in transparency.

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 concise, comprising two sentences that front-load the purpose and then outline the workflow. Every clause adds value, from 'look up / search' to 'pass the cn_code to calculate_cbam_liability', with no redundancy.

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 simplicity and a rich schema, the description is largely complete. It communicates the search process and implied result fields (code, CBAM status, sector). The lack of an output schema means the return structure is not explicitly described, but the description still provides enough context for basic usage.

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 all 4 parameters with 100% description coverage, including examples and defaults. The description adds only the workflow context of passing cn_code to calculate_cbam_liability, which is useful but does not enhance parameter-level semantics beyond what the schema already provides.

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's function: looking up EU CN codes for CBAM, finding the 8-digit code, checking CBAM phase 1 status and sector, and passing the code to calculate_cbam_liability. This specific verb+resource combination distinguishes it from siblings like lookup_cbam_carbon_prices and lookup_emission_factors.

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 provides clear context for when to use this tool: as the precursor to calculate_cbam_liability, for checking CN codes and CBAM status. It implicitly excludes other lookup tools by focusing on CN code search, but does not explicitly name alternatives or exclusion conditions.

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