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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so safety is covered. The description adds behavior the annotations do not: results are sorted newest first, the full history is retained ("every recorded version" — no truncation), and retention exists to make past calculations reproducible. It omits pagination behavior, which is the main remaining gap.

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 short sentences, front-loaded with what is returned and its ordering, followed by the rationale. The Chinese text is a verbatim translation rather than added information, so it duplicates tokens, but the English portion itself has no waste.

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 one-parameter, read-only, closed-world listing tool with 100% schema coverage and full annotations, the description supplies the ordering and retention rationale an agent needs to use results correctly. Only the return shape (what a version record contains) and pagination are unaddressed, and with no output schema that is a minor omission for a simple list.

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%, and the schema already says factor_id comes from search_emission_factors, so the baseline of 3 applies. The description's only added nuance is "one factor," reinforcing that factor_id is a single value rather than a list, which is marginal but real.

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?

"List every recorded version of one factor, newest first" names a specific verb (list), a specific resource (recorded versions), a scope (one factor), and an ordering. That is distinguishable from search_emission_factors (search) and get_emission_factor (current value) without opening any schema.

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 line "Old versions are kept so past calculations can be reproduced" implies the use case (audit/reproduce a historical calculation), but it never states when to pick this over check_factor_updates or get_emission_factor, and gives no exclusions. Usage is inferable rather than prescribed.

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