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

With no annotations present, the description carries the transparency burden well: it discloses the calculation formula, the special currency/year requirement, and notes that no FX conversion is applied. It does not explicitly describe return value structure, but the formula and tool context make the calculated result reasonably clear.

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 dense sentences deliver the formula, the core caveat, and a cross-tool pointer with a concrete example. Every clause creates value, with no wasted words.

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 only two required parameters, no annotations, and no output schema, this description is largely sufficient. It covers the method, prerequisites, and lookup path; the only obvious improvement is a short explicit statement of the returned quantity—estimated emissions—though the formula already implies it.

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; the description adds more value by explaining that factor_key must be a 'spend_based' EEIO sector factor, providing a fully qualified example key, and by stating that spend must match the factor's currency/year. This goes beyond the schema's minimal descriptions.

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 exactly what the tool does: it calculates spend-based EEIO Scope 3 emissions using a clear formula (emissions = spend × economic-intensity factor). It also distinguishes itself from sibling calculation tools by emphasizing the spend-based approach and giving a concrete sector factor example.

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 clearly indicates when this tool is relevant—for spend-based screening—and provides a direct pointer to search_factors for finding sector factors. It also gives an important usage caveat about matching currency/year, though it stops short of explicitly saying when not to use this tool vs. activity-based alternatives.

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