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

Annotations already declare destructiveHint=true and idempotentHint=false, so the safety profile is covered. The description adds one useful consequence, 'asset returned', but says nothing about reversibility, the effect on pending offers, or authentication beyond the schema's key field.

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 definition is short, front-loads the WHEN condition, and includes a compact example. The leading 'bazaar_cancel_listing.' token is redundant, but otherwise every sentence carries decision-relevant information.

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, two fully documented parameters, and annotations covering safety and idempotency, the description supplies enough for an agent to call the tool correctly. The remaining gap is the lack of detail on side effects for outstanding offers or proposals.

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%, with both key and listing_id documented, so the baseline is 3. The example invocation shows the listing_id wire format, which adds mild value, but the key parameter's role is left entirely to the schema.

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 states a specific verb and resource: the seller cancels an open listing. It distinguishes itself from bazaar_edit_listing and bazaar_deregister, though the opening restatement of the tool name and the terse 'deregister target=listing' phrasing slightly weaken an otherwise clear purpose statement.

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 an explicit WHEN condition ('seller cancels an open listing') and names two alternatives with their differences: edit_listing keeps the listing listed, and deregister target=listing follows the same cancel path. There is no explicit when-not, and the deregister equivalence is ambiguous enough to require guessing.

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