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

Beyond the annotations (readOnly, idempotent, non-destructive), the description discloses meaningful runtime behaviors: disabled benefits return zeroed values and are unusable, unused units accumulate up to three monthly grants while enabled, and the values are not generation credits. This is valuable, non-obvious context.

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?

Four sentences, each carrying essential information, with the core purpose front-loaded. There is no filler, repetition of the title, or irrelevant detail.

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 parameterless read-only tool, this description fully equips an agent: it explains what is returned, how disabled benefits are represented, accumulation behavior, and what the data is not. Nothing essential 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?

There are no parameters, so the schema has nothing to document and the baseline is 4. The description adds useful semantics about what the response covers (limits, caps, balances) and how disabled benefits behave, which compensates for the absence of an output schema.

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 clearly states a specific action ('Read') and a specific resource ('currently enabled subscriber benefits') and distinguishes this from generation credits. This makes the tool's purpose unmistakable even among many sibling tools like get_credits.

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 description gives strong contextual guidance by stating what the tool reads and explicitly noting 'These are not generation credits,' which helps an agent avoid confusing it with get_credits. It does not name an alternative tool explicitly, but the boundary is clear enough for selection.

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