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

Adds real behavioral detail beyond annotations: partial-update semantics ('Changes the fields you pass and leaves the rest'), the immediate buyer-visible side effect of price changes on an active listing, the confirmation requirement, and the API key/auth dependency. Annotations only supply readOnly=false, openWorld=true, destructive=false, so this description carries meaningful extra context.

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 core purpose well, but the confirmation requirement is spread across two overlapping sentences ('By default you confirm each call; you can switch that off' and 'Reaches other people: confirm with the user before each call'), which is redundant.

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 2-parameter, 100%-schema-covered mutation tool with no output schema and partial annotations, the description covers partial-update behavior, side effects, auth, and confirmation. It is largely complete, with only the lack of alt-tool routing as a gap.

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 already 100% (baseline 3), and the description adds useful semantics: it clarifies the unit for pricing ('Price is in US cents') and restates the accepted field set, which helps map intent to the string 'fields' parameter.

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 (change) and resource (a listing), and enumerates the exact fields affected (title, description, price, additional license price, grades, subjects, tags). It implicitly excludes status changes, which is the sibling set_product_status's job, though it never names that alternative 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?

Provides context about confirmation ('By default you confirm each call... you can switch that off') and protagonist impact ('Reaches other people: confirm with the user before each call'), but gives no explicit when-to-use versus alternatives guidance (e.g., when to use this instead of create_product or set_product_status).

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