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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered structurally. The description usefully adds what the response conceptually contains (invoiced total vs. outstanding) and notes the underlying SOAP call, but says nothing about currency, zero-balance behavior, or error cases for an unknown customer code.

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 terse sentences, the payoff definition front-loaded and the SOAP provenance relegated to a trailing note. Nothing wasted.

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 read-only single-parameter tool with no output schema, the description conveys both the input (one customer) and the shape of the answer. Minor gaps like currency/zero-balance handling keep it from a 5.

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?

With one parameter at 100% schema coverage (including an example value 'ACME01'), the schema carries the semantics. The description adds no extra meaning about customer_code, so the baseline 3 applies.

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+resource and even spells out the two values returned (total invoiced value, outstanding balance), which distinguishes it from kashflow_get_customer and the invoice-listing siblings. It does not explicitly name a sibling it replaces, keeping it at 4 rather than 5.

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 phrase 'What one customer owes' implies a collections/AR context, but there is no explicit when-to-use, when-not, or pointer to alternatives like kashflow_get_aged_debtors or kashflow_list_customer_invoices. Usage is only implied.

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