Receivables aging across all customers

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

Annotations already declare readOnlyHint, idempotentHint and closed-world, so safety and repeatability are covered. The description adds genuinely useful behavior — results are bucketed by days overdue and evaluated as of a supplied date — but never defines the bucket boundaries or says whether zero-balance or credit-balance customers appear, which is what an agent would actually need to interpret the output.

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, no filler, with the core behavior stated first and the usage discriminator second. Nothing could be cut without losing information.

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?

For a one-parameter read-only tool with full schema coverage and annotations carrying the safety profile, the description covers purpose, scope, and result shape. The only real gap is bucket definitions, which matters for interpreting output that has no output schema to explain it.

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?

Single parameter with 100% schema description coverage, so the schema already explains asOfDate including its date format pattern. The description only echoes that with "as of a date" and adds no format, timezone, or default semantics. Baseline 3 is correct.

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 verb (returns), a specific resource (aging profile of all outstanding receivables), and a specific transformation (bucketed by days overdue). The scope word "all" plus the exclusion of single-customer use makes it immediately distinguishable from getCustomerSummary and getPaymentHistory.

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 second sentence gives an explicit selection rule: portfolio-level questions, not single-customer ones. That is a real when-to-use plus a when-not. It stops short of naming the sibling tool that handles the single-customer case, so the agent must infer the alternative rather than being routed to it.

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