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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds one useful behavioral detail, the 30-day default window, but says nothing about data retention, aggregation timezone, pagination, or whether results are truncated.

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?

A single compact sentence that front-loads the returned metrics and ends with the default window. Nothing is wasted, though the fragmentary phrasing means the reader has to supply the implied verb.

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?

One optional parameter plus an existing output schema means the description needn't explain return shape, and it correctly covers the default. The remaining gap, when to prefer this over get_balance or get_account, is a usage-routing issue rather than a completeness failure.

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 must carry the parameter meaning, and it does: 'days' is the lookback window measured in days and defaults to 30. It does not mention the schema's maximum of 90 or the minimum of 1, so the constraint still lives only in the 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 the resource concretely: API call counts broken down by operation and send counts broken down by target. It is clear what data the tool exposes, but it uses a noun phrase with no action verb and never distinguishes itself from siblings like get_balance or get_account, which likely also report aggregate metrics.

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 guidance on when to call this tool instead of get_balance, get_account, or other reporting siblings, and no stated preconditions. The agent must infer the use case purely from the metric names.

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