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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds value beyond them by noting the response carries 'data freshness', implying a timestamped snapshot rather than live data. It stops short of describing staleness bounds or refresh cadence, so it is not a full 5.

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 metric enumeration is long but earns its place by telling the agent exactly what the single call returns, and the routing sentence is front-loaded at the end. Slightly list-heavy, but no sentence is 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?

There is no output schema, so the description's field enumeration and freshness note are what tell the agent what comes back, which is exactly the coverage needed. Zero-parameter, read-only tool: nothing material 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 the baseline is 4; there is nothing for the description to clarify about inputs. The schema coverage signal is moot with an empty property set.

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 specific verb ('Headline numbers ... in one call') and enumerates the exact resources covered: supply, circulating vs locked, holders, Agents, epochs, swap offers, chain height. It is clearly distinguishable from the sibling epoch and swap tools without opening a 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?

Explicitly says 'Use it first to orient' and names the two sibling alternatives (get_epoch, get_current_epoch) with the condition that selects each. Both when-to-use and when-to-use-something-else are covered.

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