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

Annotations already declare readOnlyHint=false, destructiveHint=false, idempotentHint=false, and openWorldHint=false, so the safety profile is covered. The description adds the useful fact that the call returns a meter_id, but does not say what happens if a meter already exists, whether authorization is needed, or that repeat calls will create duplicates. Against already-declared annotations this is adequate but not rich.

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?

Three short, front-loaded statements with no filler: purpose first, then the two non-obvious parameter semantics, then the return value. Every sentence adds information an agent would not otherwise have.

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?

An output schema exists, so return-value detail is not required, yet the description still notes the meter_id return. For a six-parameter mutation tool with full annotation coverage, the remaining gaps (sla_target meaning, duplicate-creation behavior) are modest rather than disqualifying.

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?

Schema description coverage is 0%, so the description carries the burden and does partially compensate: it defines 'unit' with concrete examples and clarifies that price_minor_per_unit is in minor currency units (cents) per unit, which prevents a 100x pricing error. However, sla_target (default 0.99) is never explained, and currency is only implied by the cents remark, leaving two of six parameters undocumented.

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 gives a specific verb and resource ('Create a usage meter') plus the two parties it binds (provider and consumer agent), so an agent can distinguish it from list_meters, flag_meter, record_usage, or close_period. It stops short of explicitly naming a sibling or stating the setup ordering, so it is clear but not fully differentiated.

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?

There is no when-to-use guidance, no precondition (e.g., that a meter must exist before record_usage or that duplicates are not caught because the call is non-idempotent), and no mention of alternatives such as list_meters to check for an existing meter. Usage is only inferable from the tool name.

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