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

Annotations already declare readOnlyHint=true and openWorldHint=false, and the description goes beyond them by pinning the aggregation window to UTC months and explaining the '-agent' plan-label bucket and that such traffic is counted and billed like any request. It still omits pagination/limit behavior and the fact that a dashboard key is needed for authorization.

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 sentences, front-loaded with the resource and window, followed by the one non-obvious special case. The parenthetical earns its space because the agent bucket is otherwise undiscoverable.

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?

There is no output schema, so the return shape (one row per group with counts/costs) is never described, and the auth requirement for dashboard_key is unstated. Adequate to select the tool, thin on what comes back.

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 coverage is only 40% across five parameters. The description reinforces month (UTC) and group_by values but mostly restates what the schema already says, and it says nothing about the required slug or dashboard_key, nor about the limit cap of 200.

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?

States a specific resource and scope: monthly usage for one API, grouped by customer/endpoint/plan. An agent can tell what it returns, but nothing distinguishes it from the sibling export_usage, which is likely the closest alternative.

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 read-only reporting intent is implied by 'usage ... grouped by', but there is no explicit when-to-use statement and no mention of when to prefer export_usage or get_ingest_snippet. Usage must be inferred from the name and grouping options.

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