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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=true, so the safety profile is covered and the trailing 'Read-only' is redundant. What the description does add is scope (own account only) and the shape of the returned metrics, but it does not disclose the time window, data freshness, or whether currencies are converted — meaningful gaps for a financial summary.

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?

One front-loaded sentence enumerating the exact outputs, followed by a two-word read-only tag. No filler; every clause identifies a distinct part of the return value.

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?

With no input params and no output schema, the description carries the burden of describing return values, and it does so at a useful level (MRR and ARR by currency, top plans, trialing/past-due counts). It stops short of stating the reporting period or how 'largest plans' is ranked, which are the remaining ambiguities.

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 tool takes zero parameters and the schema coverage is 100%, so the baseline is 4. The description correctly implies no filtering input is needed, consistent with the empty 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?

States a specific metric family (MRR/ARR per currency, largest plans, trialing/past-due subscription counts) scoped to the user's own Stripe account. That content signature clearly separates it from sibling summaries such as stripe_churn_summary, stripe_failed_payments, and the generic stripe_api_read.

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?

Usage is only implied: an agent can infer 'call this when you need revenue metrics,' but the description never says when to prefer it over stripe_churn_summary, stripe_account_info, or stripe_api_read, and gives no preconditions. Adequate but with a clear routing gap.

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