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

Annotations already establish it is a write operation (readOnlyHint=false) that is non-destructive and open-world. The description adds real behavioral context beyond that: the proposal is sent to the listing's owner, who is notified by email, and a pending proposal can later be withdrawn.

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?

Four tight sentences with no filler; the triggering condition is front-loaded, followed by side effects, the confirmation prerequisite, and the follow-up action. 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?

An output schema exists, so return values need not be explained. The description covers trigger, side effects, required user confirmation, and the withdrawal path, leaving nothing an agent needs missing.

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 each parameter is already documented, and the description's note that offering one's own listing is optional only restates what the schema's required list shows. No additional syntax or constraint detail is provided beyond 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?

States a specific verb and resource ('propose a barter trade for someone else's listing') plus the optional exchange of the user's own listing. This clearly distinguishes it from siblings like counter_proposal, accept_proposal, and create_listing.

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 says when to use it ('when the user wants to propose a barter trade'), adds a prerequisite ('Confirm with the user which listing... before calling'), and routes to the alternative 'withdraw_proposal' for pending proposals. When/alternatives are both covered.

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