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

Annotations already establish readOnlyHint and openWorldHint=false, so the safety profile is covered. The description adds real business context not in the structured fields: personal is the default tied to credits and card one-off purchases, commercial is a business licence sold by card where price.commercial is offered, and a version lets you read historical terms. Minor gap: no statement on caching or whether terms can change mid-version.

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 resource definition followed by usage triggers and the parameter vocabulary. It is dense but no sentence is filler; the parenthetical 'the default' inside the code explanation is slightly compressed for readability.

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 an output schema present, the description need not describe return shape, and it correctly focuses on when to call and what the code values mean. A gap remains around whether a different code must be requested for the same image or whether both are usually needed together.

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 baseline is 3. The description goes further by explaining what each code actually means commercially (personal = credits/card one-off, commercial = business licence) and reinforcing the default, which the schema states only tersely as 'Omit for personal.'

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 opening clause defines the resource precisely: 'The full terms an image is sold under: what the buyer may and may not do with it.' That is clear verb+content, and it is distinguishable from siblings like create_checkout by framing this as the read side of a purchase. Sibling differentiation is implied rather than spelled out, which keeps it just short of a 5.

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?

It gives two concrete triggers: 'Read this before recommending a purchase' and 'whenever the person asks what they are allowed to do with an image.' No explicit exclusion or named alternative is given, so it stops short of the when/when-not/alternative bar, but the positive guidance is unusually specific.

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