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 only the underlying endpoint (POST /usage/) and the fact that results are aggregated and optionally grouped, but says nothing about pagination, result size limits, or how take_limit/take_is_ascending interact with grouping.

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 tight clauses with the core purpose front-loaded and no filler. The trailing 'API: POST /usage/' is low-value metadata for an agent choosing a tool, but it costs little.

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 9-parameter tool with a nested filter object and no output schema, the description is adequate but thin: it doesn't characterize the aggregated response shape or the interaction between take_limit and group_by. Rich schema coverage compensates for the parameter gap, keeping this at minimum viable.

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 100%, so every parameter is already documented in the schema, including defaults for end_time_in_seconds and the sort default for take_is_ascending. The description adds no parameter-level detail beyond what the schema provides, so the baseline 3 applies.

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+resource ('Query aggregated usage for a single meter') with scope ('over a time range, optionally grouped/filtered'), which implicitly separates it from the sibling amberflo_get_all_usage. It stops short of explicitly naming or contrasting with any sibling, so it lands at clear-but-undifferentiated.

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?

'for a single meter' implies the contrast with amberflo_get_all_usage and amberflo_explain_usage, but no alternative is named and no when/when-not condition is stated. Usage is implied rather than guided.

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