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

Annotations already cover read-only, idempotent, non-destructive, closed-world behavior, so the safety bar is low. The description adds real value beyond that by disclosing the content of the response (size, freshness, gaps, standing caveats) and by flagging that results carry known caveats rather than being raw counts.

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 tight sentences: the first states what is returned, the second states when to call it. No preamble, no redundancy, front-loaded with the payload description.

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 must carry the return-value burden, and it enumerates the four categories of information returned (size, freshness, gaps, caveats), which is sufficient for an agent to decide to call it. Exact response shape remains unknown, but this is a low-complexity zero-param read tool where that gap is minor.

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 the schema baseline is 4. The description correctly implies a no-argument, whole-index query with no scoping options.

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 concrete verb and payload: it reports size, freshness, gaps and caveats of the newspaper index. This clearly distinguishes it from retrieval siblings like fetch, get_page, or search_newspapers. It falls short of a 5 only because "index" is somewhat abstract and the sibling naming is only implicit ("judge what an empty search means").

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 explicit triggering contexts: questions about what the index covers, how current it is, or how to interpret an empty search result. It does not name a specific alternative tool or state when NOT to use it, so 4 rather than 5.

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