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

Annotations already mark readOnlyHint=true, but the description adds meaningful context: the operation is read-only by design, changes are done by a human in the web app, and the return shape is disclosed (one entry per category with count, maximum, and unlimited status). This goes beyond the annotation without contradicting it.

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?

Every sentence earns its place: the first sentence states purpose and output shape, the second gives a concrete use case, the third routes to the correct sibling, and the fourth adds context and read-only constraints. The key distinction is front-loaded.

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 zero-parameter read-only tool with no output schema, the description is complete: it explains what the tool returns, why it is used, when to prefer a sibling, what context is required, and what is intentionally out of scope. 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 input parameters, so the schema carries no parameter semantics. The description adds the important invocation requirement of organization context and explains what the returned entries contain, compensating fully for the empty input 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 names a specific verb and resource ('Get current usage against the plan limits') and adds precise scope: one entry per category with current count, maximum, and unlimited flag. It also distinguishes itself from the close sibling get_credit_balance, so an agent can pick it out from the large get_* sibling set.

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?

It explicitly says when to use this tool ('Use this for usage against plan limits') and names the alternative for AI credit balance ('use get_credit_balance'). It also states the requirement of organization context and clarifies that plan, seat, and top-up changes are intentionally not available through MCP.

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