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

The description discloses billing behavior (500 micro-dollar credits per successful call), prerequisites (credits, Authorization header), and the idempotent recovery pattern (reuse requestId; new requestId is new billable operation). It also clarifies that missing costs remain unknown, which is a behavioral trait not evident from annotations. No contradiction with annotations (idempotentHint true aligns with recovery).

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?

The description is compact, with each sentence carrying essential information: purpose, cost, prerequisites, and recovery. It is front-loaded with the core purpose. It could be slightly more structured (e.g., separating payment info from usage steps), but it's not verbose or redundant.

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?

Given the complexity (nested input object, 3 top-level parameters, output schema present), the description covers key operational aspects: payment, prerequisite steps, recovery, and the tool's core behavior. It does not explain the output schema, but that is available in the schema itself. It lacks explicit error-handling guidance, but overall it is sufficient for correct invocation.

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 description coverage is 67% (two of three top-level parameters have descriptions). The description adds general context about the purpose of the input (reconciling amounts) but does not explain each nested parameter's semantics beyond what the schema already specifies. It adds minimal additional value for the input object, so a 3 is appropriate.

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 states a specific verb ('Reconcile') and clearly lists the resource types (item, discount, shipping, tax, fee) and the intended outcome (check declared totals). It distinguishes the tool from siblings by its focus on price component reconciliation, making its purpose unambiguous even without comparing to alternatives.

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 explicit usage flow: call agent_utilities_prepare first, then use the returned requestId. It also specifies prerequisites (existing credits, private Authorization header) and recovery guidance (reuse prepared arguments). However, it does not explicitly state when to avoid this tool or compare to alternative siblings, so it's slightly less than a perfect 5.

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