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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description adds useful context not in annotations – the required 'orders:read' scope and that the record is durable and carries the expiry – but says nothing about failure behavior when a purchase_id is unknown or expired.

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 tight sentences with no filler; the resource and scope are front-loaded and every clause carries information.

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 one-parameter read with annotations covering safety and no output schema, the description is roughly sufficient. The gaps are the undocumented purchase_id provenance and the lack of disambiguation from the three sibling get_*_purchase tools.

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 single parameter purchase_id (uuid) is never mentioned in the description. It doesn't say where the id comes from (e.g., a prior buy_board_post_time or list_orders call), which is the one thing an agent needs to invoke this correctly.

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 (retrieve) and resource (this agent's durable post-time purchase record) plus what the record contains (purchased expiry). This distinguishes it from get_board_pass_purchase and get_credit_purchase by resource type, though it doesn't name those siblings explicitly.

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 prerequisite scope 'orders:read' is given, which helps an agent know if it can call it at all. However, there is no guidance on when to use this versus the closely named get_board_pass_purchase, get_plan_purchase, or get_credit_purchase, leaving selection to inference from the resource name.

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