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

Annotations already establish that this is read-only, idempotent, and non-destructive. The description adds meaningful behavioral context beyond annotations by specifying that results are grouped per currency and never summed across currencies, and by listing the heterogeneous sources of upcoming payments. This is sufficient for a read-only query tool.

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 compact sentences carry the full meaning: the first defines scope and contents, the second states a key aggregation rule. No filler or redundancy; the most important information is front-loaded.

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 annotations covering safety and an output schema available, the description does not need to explain return values. It gives a useful enumeration of result categories and the currency behavior. The only missing piece is the default window when 'days' is not supplied, which prevents a perfect score for a single-parameter tool.

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 schema has 0% description coverage, so the description must clarify the 'days' parameter. It does so by saying 'in the next N days', mapping N directly to the parameter. However, it does not state the behavior when the parameter is omitted, even though the schema marks it as optional, leaving a small but real invocation ambiguity.

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 clearly states what the tool does: it surfaces upcoming obligations within a configurable time window and enumerates the exact categories included (recurring rules, planned expenses, reminders, card due dates, loan payment days). This makes it readily distinguishable from siblings like list_recurring_rules or record_loan_payment.

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 description provides clear context for when to use the tool: whenever the user wants to know what is due in the next N days. It does not explicitly name alternatives or exclusion conditions, but the scoped purpose and the 'never summed across' caveat give adequate practical guidance without requiring inference.

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