update_item

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

With no annotations, the description carries the full burden, and it delivers real behavioral context: partial-update semantics ('Only the provided fields are sent') and a non-obvious business rule (title updates rejected once units are sold). It stops short of stating auth/permission requirements or failure/reversibility behavior, so it is strong but not exhaustive.

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, then the sibling routing rule, then the gotcha, then the return shape, in four dense sentences with no filler. Every sentence 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?

No output schema exists, and the description compensates by naming the returned fields (id, price, available_quantity, status). It covers partial-update semantics and the key business constraint; only permission/error-handling context is absent, which is a minor gap for a mutation tool.

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 100%, so every parameter is already documented in the schema, including the title's no-sales constraint and the site-prefixed item_id format. The description adds little beyond restating field names, so the baseline 3 applies.

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 (update) and resource (an existing listing owned by the authenticated seller) and enumerates the mutable fields: price, stock, title, video. It explicitly distinguishes itself from the sibling update_item_status, so an agent can route correctly without opening either 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?

Explicitly names when to use it ('price changes and stock adjustments') and when to use the alternative instead ('to change visibility (pause/activate/close) use update_item_status'). This is the when/when-not/alternative pattern at full strength.

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