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

Annotations already declare readOnlyHint=true and idempotentHint=true, so the safety profile is covered. The description adds useful behavioral context by specifying that the data is scoped to the signed-in host and reflects the current month's usage, which implies time-dependent data. However, it does not describe response structure, potential absence of plan limits, or any edge behavior such as what happens when the host has no plan.

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 a single compact sentence that front-loads the subject (the signed-in host) and quickly enumerates the three key result categories: plan tier, trial status, and usage against plan limits. Every phrase earns its place; there is no repetition, filler, or schema duplication.

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 summary tool, the description is adequately complete. It describes what the response covers and the scope ('signed-in host'), and the annotations cover the operational safety. The absence of an output schema is mitigated by the explicit enumeration of the result content, though a note on the format of usage limits would make it fully self-contained.

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 has zero parameters, so parameter disambiguation is unnecessary. The description correctly focuses entirely on the output semantics, which is the appropriate baseline for a parameterless read-only tool. No parameter-related ambiguity exists.

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 identifies the tool's purpose: retrieving the signed-in host's plan tier, trial status, and current usage against plan limits. It names the specific resource (usage summary) and the data domains (properties, templates, bookings), which distinguishes it from sibling listing tools. It lacks an explicit verb like 'retrieves' or 'gets', but the tool name and content specification make the purpose unambiguous.

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 provides no guidance on when to use this tool versus alternatives such as list_bookings or list_properties. It implies it is for account-level usage/limit checking, but does not state explicit conditions, exclusions, or comparison with sibling tools. An agent would need to infer from the tool name that this is for plan usage rather than operational data.

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