Failed payments

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

Annotations already cover read-only, idempotent, non-destructive and open-world access, so the description only needs to add operational detail — and it does: result ordering (newest first), what still counts as failed (open or uncollectible), and the important caveat that totals cover every match while `limit` only truncates the invoice list. It stops short of stating rate limits or what an empty result means.

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 dense sentence that front-loads the selection criteria and ordering, closes with the totals-vs-limit caveat, and contains no redundant restatement of the name or title. Every clause carries information an agent could act on.

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?

No output schema exists, yet the description names the returned fields (amount, customer, attempt count) and explains the totals-versus-list relationship, which is adequate for a two-parameter read tool. Missing only minor items such as pagination behavior beyond `limit` and the shape of an empty result.

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 100% with ranges and defaults already documented, so baseline would be 3. The description goes beyond that by explaining what `limit` actually truncates (only the invoice list, not the totals) and framing `days` as a look-back window ending now — semantics the schema text alone does not spell out.

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 (invoices that Stripe tried to collect and remain unpaid in the last N days) plus the selection criteria (open or uncollectible) and ordering (newest first). It is visibly distinct from aggregate siblings get_mrr, get_churn and revenue_summary, which return metrics rather than a list of invoices.

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 scope statement implicitly tells an agent this is the invoice-level detail tool rather than a revenue/churn aggregate, but there is no explicit 'use this when…' guidance or named alternative. Neither the description nor the siblings are cross-referenced, so routing relies on the agent inferring from the resource noun.

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