Trigger a refund

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

With no annotations, the description carries the full behavioral burden. It does disclose one non-obvious trait — the reason string is written to the audit log verbatim — but says nothing about irreversibility, required permissions, idempotency, or the speed/finality of the refund, which are exactly the traits an agent needs before moving money.

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 tightly written sentences, front-loaded with the action and followed immediately by the one behavioral nuance that changes how the agent fills a parameter. No filler, no repetition of the title.

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?

An output schema exists, so return values need not be explained. However, for a financial mutation with zero annotation coverage, the description omits the safety-critical context (irreversibility, authorization, whether a repeat call double-refunds), leaving an agent under-informed on the risky parts.

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%, so the baseline is 3, but the description adds genuine meaning: the reason parameter is persisted verbatim to the audit log, which tells the agent to write an explanatory, human-readable justification rather than a terse code. The other two parameters (amount, customer_id) are fully specified in the schema and need no extra narrative.

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 ('Issue') and resource ('a refund against a customer's account'), so an agent can tell exactly what the tool does. There are no sibling tools to distinguish it from, so the ceiling of 5 (sibling differentiation) isn't reachable here.

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 gives no when-to-use guidance, no prerequisites, and no alternatives or exclusions. The only usage-adjacent signal is implicit ('the reason ... should say why the refund is warranted'), which is content guidance for a parameter, not selection guidance.

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