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

Annotations declare readOnlyHint=false, destructiveHint=false, idempotentHint=true. The description adds important behavior beyond that: creates a persistent sandbox receipt, debits an authorized agent test budget, and never transfers real funds. These side effects are not inferable from the annotations, and the description does not contradict them.

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, front-loaded with the action and key limitation ('Never transfers real funds'). No waste; every clause adds crucial information. The structure is efficient and scannable.

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?

The description discloses main side effects but omits both parameter semantics (see above) and return value details (no output schema). It also does not address usage relative to siblings. Given the tool's simplicity (2 params, no nested objects) and that the safety profile is clear, it is partially complete but not fully self-sufficient.

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 0%, and the description does not mention either 'since' or 'idempotency_key'. The schema provides only format patterns (date format, key pattern) without semantic meaning. The description fails entirely to compensate for the lack of parameter documentation, leaving the agent without guidance on what these parameters represent or how to use them.

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 clearly states a specific verb (simulate purchase) on a specific resource (Evidence Pack) and adds concrete consequences (creates receipt, debits budget). It does not explicitly name sibling alternatives, but the resource name 'Evidence Pack' distinguishes it from purchase_changes and purchase_snapshot, so purpose is unambiguous.

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?

No explicit guidance on when to use this tool versus siblings like purchase_changes, purchase_snapshot, or get_free_sample. The term 'sandbox' implies a testing context, but the description does not state conditions for selection or exclude any alternatives, leaving the agent to infer usage.

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