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

Beyond the annotations (readOnlyHint, idempotentHint, openWorldHint, destructiveHint=false), the description adds real behavioral detail: the channel header is resolved internally, an UnknownProduct outcome comes back as Success=false rather than an exception, and OtherUrls may appear so extension clients can offer bulk publish. It could have explicitly noted that the POST verb is a query/read operation so an agent doesn't mistake it for a mutation, but nothing here contradicts the annotations.

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?

The Purpose/ownerAgent/Use when/Input/Output block layout is front-loaded and scannable, which is good. But boilerplate such as 'This is an explicit tool with a fixed endpoint; it is not a generic endpoint caller' and the trailing 'Search terms: channellisting list' add no decision-relevant information, and the 'Send the exact request payload in body' line repeats the schema requirement.

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 two-parameter tool with an output schema, the description covers the input contract, the success path, and the main failure path, so an agent can call it and interpret results correctly. The only real gap is that it never reconciles the 'List' in the tool name with single-URL resolution, which risks confusion against the bulk listing siblings.

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%, but the `body` parameter is an untyped object in the schema, so the description is the only source of its internal structure. It supplies that with 'ListRequest body with Url and optional extension ExtraData' and reiterates that the channel header is the current ChannelOAuthId resolved internally. This adds genuine meaning over the schema rather than restating it.

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 description names a concrete verb and resource: 'Resolves one supplier product URL into validated product data for listing creation.' That is far more informative than the opaque name 'Post Channellisting List', which would otherwise be unreadable. It distinguishes itself from the many bulk/listing-management siblings by emphasizing 'one concrete supplier product URL', though it never names an alternative tool 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?

'Use when: Use when a user has submitted one concrete supplier product URL and needs the product data required to prepare a listing' gives a clear triggering condition. The output section also describes the boundary cases (UnknownProduct with no OtherUrls, non-product pages returning OtherUrls), which helps an agent interpret results. What's missing is any explicit routing to competing tools (e.g., catalog getproducts or the bulk searchproduct tools) for the multi-URL case.

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