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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, and openWorldHint=false, so safety is covered. The description adds genuine behavioral context beyond that: it says the record is the 'original government record', flags 'whether it can be used for calculation directly', and discloses 'usage limits' on the factor, which affects downstream use. It does not describe failure behavior for an unknown ID.

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 content is front-loaded and the field list is efficient, but the entire description is duplicated verbatim in Chinese and English, roughly doubling length without adding information. Structure is sound; redundancy is the cost.

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?

With no output schema, the description usefully enumerates what the response contains, which is exactly the burden it must carry. Combined with the required-ID prerequisite and the version default from the schema, an agent can call it correctly; only error and not-found behavior is left unaddressed.

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%: factor_id already states it comes from search_emission_factors, and version already documents that omitting it yields the current version. The description reinforces that factor_id is the lookup key but adds no new semantics for the version parameter, so the baseline of 3 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 names a specific verb and resource (get one emission factor by ID) and enumerates the payload fields returned: government record, unit, applicable year, boundary, source, version, calculability, and usage limits. It does not explicitly distinguish itself from near siblings such as get_electricity_factor, so it falls short of full sibling differentiation.

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?

It gives an explicit prerequisite workflow: 'Find the ID with search_emission_factors first', which routes the agent to the correct discovery tool before invoking this one. It does not state when not to use this tool (e.g., when to prefer get_electricity_factor or list_factor_versions), so it stops short of full when/when-not guidance.

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