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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is largely covered. The description still adds real value beyond them by stating that it cannot trigger a sync and by describing the three status dimensions returned, which appear nowhere else since there is no output schema.

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 English text is front-loaded and every sentence carries information: purpose, three status fields, and the read-only limit. The only waste is the full Chinese restatement, which inflates length but appears to be a deliberate bilingual mirroring convention rather than filler.

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 parameters and no output schema, the description must carry both the purpose and a sketch of the return value, and it does list the status fields an agent needs. The main omission is scope: it does not say whether all official sources are covered or whether the result can be empty, which matters for interpreting the response.

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 tool takes zero parameters, so there is nothing for the description to disambiguate and the baseline of 4 applies. The description correctly focuses on return semantics instead of inventing parameter detail.

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 gives a specific verb and resource ('show the sync status of each official source') and enumerates exactly what status means: last-checked time, possible staleness, and a pending unreviewed difference. That enumeration distinguishes it from siblings like list_data_sources or get_emission_factor, which return data rather than freshness/review state.

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?

Usage is only implied: the tool is framed as a status/health check for official sources, but the description never says when to call it (e.g. before a calculation, after a sync) or names an alternative such as list_factor_versions. The negative guidance ('cannot trigger a sync or write anything') clarifies limits but not when-to-use.

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