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

Adds substantial behavior beyond the annotations: ~15 min link lifetime, single-purpose scope, ownership proven by an unguessable credential, and crucially that 'each call consumes one of the limited downloads' — which explains why readOnlyHint=false despite a GET-like verb. openWorldHint=true is not elaborated (no rate-limit or failure-mode detail), keeping it short of a 5.

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-loads the 'AUTHENTICATED' precondition, then delivers scope, credential mechanism, side effect, and exclusion in four dense but waste-free sentences. Every clause earns its place.

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 return-value burden and does so ('signed download link', ~15 min lifetime). Auth, scope, and the download-consumption side effect are all covered, leaving nothing an agent needs to call it correctly.

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 the baseline is 3; the description goes slightly further by framing session_id and download_token as alternative ownership credentials (an OR relationship) and noting email is audit-only. Most per-parameter detail still lives in the schema, so it adds only modest value.

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 and resource ('returns a short-lived signed download link for THEIR order only') and clearly distinguishes itself from listing/browsing siblings via 'Cannot list or access other purchasers' orders.' An agent can tell exactly what this tool produces without opening the schema.

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?

States the precise triggering condition ('for a buyer who already completed a purchase') and an explicit exclusion ('cannot list or access other purchasers' orders'). It does not, however, name a sibling alternative (e.g., check_order_status) for the pre-purchase case, so routing is left partly to inference.

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