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

Goes well beyond the annotations (destructiveHint=true, openWorldHint=true) by spelling out that only provided fields change, that previous values are overwritten, and that the user should be asked to confirm first. It also discloses two hard preconditions (no edits during a trade, no photo changes), which the annotations cannot express.

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?

Three tight sentences, front-loaded with the trigger, then the mutation semantics, then the two exclusions. No filler and nothing an agent must skip past to find the core instruction.

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, return values need no explanation, and the annotations already flag the destructive and open-world nature. The description covers the remaining gaps for a 10-parameter partial-update tool: partial semantics, confirmation requirement, and operational exclusions.

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, but the description adds a genuinely useful semantic: it is a partial update where only supplied fields are touched and existing values are overwritten, which is not captured in the schema. It does not describe units, formats, or enum meanings beyond what the schema already documents.

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 ('change one of their own active listings'), scoping it to the user's own listings, which cleanly separates it from create_listing, remove_listing, and set_listing_status. An agent can identify the operation 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?

Gives a clear trigger ('when the user wants to change...') plus two explicit exclusions: listings in a trade in progress and photos. However, it never names the sibling tool or mechanism to use for the excluded cases, so the alternative path is only implied.

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