Check quota and balance

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

Annotations already establish readOnly/destructive/openWorld, so the safety profile is covered. The description adds real behavioral context beyond them: the response is a point-in-time entitlement snapshot ("right now") and includes a reset schedule, which tells the agent the values are time-boxed and may need re-checking.

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?

A single dense sentence pair: contents first, then the call-to-action ("Call before mastering"). No filler, no restatement of the tool name.

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 zero parameters, an output schema documenting the return shape, and annotations covering the safety profile, the description only needs to convey purpose and timing — which it does. It could note rate-limit or caching behavior for a quota check, but 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?

The tool takes no parameters, so there is nothing for the description to disambiguate; baseline 4 applies. The "this caller" phrasing usefully confirms the implicit scoping that no argument is needed.

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 states a specific scope ("what this caller may do right now") and enumerates exactly what is returned: masters left today and reset time, credit balance, upload cap, and advanced-module availability. This cleanly separates it from siblings like get_service_info (service capabilities) and get_job (job status).

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?

"Call before mastering" gives an explicit pre-condition for use, which is genuinely actionable. It stops short of naming when-not to call or pointing at alternatives, but the trigger condition is unambiguous.

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