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

Annotations already indicate non-readonly and idempotent, but the description adds critical context: no real funds transferred, and it debits an agent test budget. However, it doesn't disclose the eventual effects of repeated sandbox receipts or budget depletion.

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?

Three concise sentences, front-loaded with the core purpose. Every word earns its place, and the safety note is clear.

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 simulation tool with no output schema, it explains the key side effects (debiting test budget, no real funds). However, lack of parameter explanation is a gap, and it doesn't mention the idempotency key's role in preventing duplicate sandbox receipts.

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%, so the description must explain parameters. It doesn't mention the purpose of 'since' or 'idempotency_key' beyond what the schema provides (names and patterns). The idempotency_key is required and critical for retry safety, but the description is silent on it.

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 the tool simulates a Snapshot purchase using fictitious USDC, creating a sandbox receipt and debiting a test budget. This is specific and distinguishes it from real purchase tools like purchase_changes and purchase_evidence.

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 implies safe usage for testing without real funds, but it does not explicitly state when to choose this tool over alternatives like purchase_changes or purchase_evidence. It lacks explicit 'when not to use' guidance.

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