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

With no annotations supplied, the description carries the full burden and does so well: it explains the meaning of each returned field, that last_failed=1 signals the most recent fetch attempt failed, that the agent should flag possible staleness, and that source data can be revised retroactively. The only minor gap is that it never states the call is side-effect-free, though the read-only nature is strongly implied by the content.

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 framing sentences followed by four compact bullet lines, each covering a distinct field or caveat with no repetition. The most important information — what the tool returns and when to call it — is front-loaded before the field glossary.

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?

No output schema exists, so the description must explain the return shape, and it does by defining latest, fetched_ok, and last_failed along with their units and time zone. It is close to complete for a zero-parameter status tool; only an explicit statement about how multiple datasets are keyed in the response is missing.

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 per the baseline this scores 4. The description instead documents the output field semantics (latest, fetched_ok, last_failed), which is useful but belongs to return-value disclosure rather than parameter guidance.

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?

States a concrete verb and resource: returns the latest covered time point and last-fetched date for each dataset this service holds. That is specific enough to separate it from data-returning siblings like get_breakdown or get_report_status, which return content rather than coverage metadata.

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?

Names explicit triggers — questions such as 'how far does the data go' or 'what is the latest week', and the diagnostic case where another tool returns empty results and the period needs checking. It effectively routes the agent to this tool before or after content tools without requiring inference.

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