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

Annotations already declare the safe read-only/idempotent profile, so the description's job is to add domain behavior - and it does, explaining that paid plans keep serving past the allowance and bill the excess while the sandbox has no overage rate and stops serving entirely. That is genuinely useful operational context an agent could not derive from the structured fields. It stops short of covering freshness/latency or auth requirements.

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?

Two sentences, front-loaded with the primary metric and then the consequential billing/serving behavior. Every clause earns its place, though the '(null)' aside is a small detour into output-shape detail that the output schema already covers.

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 and an output schema present, the description need not document return values; it instead supplies exactly the missing context about how the number behaves across plan types. Nothing an agent needs to call and interpret this tool is absent.

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 there is no parameter semantics for the description to carry; the baseline of 4 applies. The parenthetical '(null)' even pre-explains an output field for the sandbox case.

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 resource and metric: this calendar month's course views measured against the plan allowance, plus the cost of excess. That is concrete enough to distinguish it from list/get tools for courses, identities or certificates. It does not, however, differentiate itself from the nearby get_overview or get_workspace_info siblings, so the agent must infer the boundary.

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?

Usage is only implied: a zero-argument, read-only tool whose purpose is self-evident from the name and description. There is no explicit 'use this when you need X' statement and no pointer to the closest alternative (get_overview) that might also report plan-level information.

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