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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds the useful detail that the freshness policy is model-declared and serves as a go/no-go signal, but says nothing about cost, latency, or scope of aggregation beyond what annotations provide.

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?

One front-loaded sentence that names the operation first and then the returned fields. It is dense but each clause carries information; the trailing relative clause about acting on figures is slightly verbose but earns its place as usage framing.

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 carries the burden of describing return values, and it does so by naming the three pieces of information produced. For a two-optional-parameter, read-only diagnostic tool this is nearly sufficient; only the all-entities aggregation behavior when entity is omitted is left to the schema.

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 both parameters are already documented (model name and entity, both optional with omit semantics). The description mentions entities and the model's declared policy but adds no formatting or scoping detail beyond the schema, so the baseline 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?

Uses a specific verb ("Report") with a concrete resource (an entity's data currency) and enumerates what comes back: last write time, row count, and the model's freshness policy. This clearly separates it from siblings such as describe_entity, sample_values, or known_gaps, though it never names those alternatives explicitly.

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 by the clause "whether figures are current enough to act on," which suggests calling it before relying on data. There is no explicit when-to-use statement, no when-not-to-use, and no pointer to a sibling for a related check.

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