usage_characters

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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is covered. The description adds the deprecation status, which is genuinely useful behavioral context, but it does not say whether the endpoint still returns data, errors out, or will be removed.

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?

It is very short, which is appropriate for a deprecated stub, but 'Deprecated' appears twice ('(Deprecated)' and 'Deprecated upstream'), which is pure redundancy rather than front-loaded signal.

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?

For a 7-parameter analytics tool with no output schema, the description should at minimum state what a caller gets back or what deprecation implies operationally. Instead it provides only a name and a status flag, leaving an agent unable to judge whether the call is worth making.

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 description coverage is 100% with 7 well-documented parameters and 3 enums, so the schema carries the full burden and baseline 3 applies. The description adds no meaning about metrics, intervals, or breakdown types beyond what the schema already states.

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 specific resource (Characters Usage Metrics) and an implied read verb, so the basic purpose is inferable. However, it does not distinguish this tool from the sibling usage_by_product_over_time, and the parenthetical repeats the deprecation twice without clarifying what is being measured or for whom.

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?

The only guidance offered is that the tool is deprecated, which weakly signals 'avoid', but no alternative or replacement is named even though usage_by_product_over_time exists as an obvious sibling. There is no statement of when this should still be called, if ever.

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