Get Usage

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

Annotations already declare readOnlyHint=true, so safety is covered. The description adds meaningful behavioral context: which metrics are included (link clicks, links created, API calls), that usage is scoped to the active billing period, and that it is per-project. This goes beyond the annotation by clarifying the operational scope and data contents, though it stops short of describing response structure or error cases.

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 description is two sentences, front-loaded with the primary action and key output details. Every sentence contributes meaning: the first states what is retrieved and the specific metrics, the second clarifies the project-level scope. No filler or redundancy.

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 simple read-only tool with one optional parameter and no output schema, the description adequately conveys the return contents (usage metrics against limits) and scope (per-project active period). It is complete enough for an agent to select and invoke the tool appropriately, though it could optionally mention whether historical periods are excluded or how limits are represented.

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 input schema already provides 100% coverage with a clear description for projectId, including the fallback behavior when omitted. The tool description does not add additional parameter semantics beyond what the schema states, which matches the baseline expectation when schema coverage is high.

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 the verb 'retrieve' and resource 'usage statistics', with specific detail on metrics (link clicks, links created, API calls) and scope (per-project, active billing period). This distinguishes it from siblings like get_subscription or list_plans, which focus on other billing aspects.

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 clearly indicates the intended use case: retrieving usage for a specific project within the current billing period. It also notes 'Usage is per-project,' implying that other tools handle subscription-wide or plan-level data, but it does not explicitly name alternatives or exclusions. This amounts to clear context without formal when-not guidance.

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