roi_trace

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

readOnlyHint already covers the safety profile, so the description earns credit for adding semantics: distinguishing cash (real money) from credit (not), and the edge case that profit fields are null when no margin is set. These are real behavioral details an agent would otherwise have to discover at call time.

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?

Front-loaded with the scope constraint, then the returned content, then the cash/credit and null-margin clarifications. Two short sentences plus a compact definition, with essentially no waste.

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 no output schema, the description carries the burden of describing returns and does so (timeline of grants, credit used, subsequent cash payments, nullable profit). Missing is an explicit relationship to the sibling ROI tools, but all information needed to call it correctly is present.

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 baseline would be 3, but the description adds a constraint the schema cannot express: 'pass exactly one' of customerRef/partnerId. Since neither parameter is marked required and nothing in the schema declares mutual exclusivity, this is meaningful added guidance.

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 (the timeline behind a credit ROI figure) and a clear scope: exactly one customer or one partner. It also names the contents it returns (grants, credit used, cash payments). It stops short of naming the sibling ROI tools (roi_summary, roi_patterns) so the boundary between them is left implicit.

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 'so you can explain why a number is what it is' implies a drill-down/explanation use case, which is useful but indirect. There is no explicit statement about when to pick this over roi_summary or roi_patterns, and no exclusion of other scenarios.

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