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

Annotations already flag non-read-only, open-world, non-idempotent, non-destructive, but the description adds the behavior that matters: automatic counter-offer negotiation bounded to three rounds, seller adjudication, and an Escrow.com transaction that releases funds only on domain delivery. It also mandates user confirmation, which is real behavioral context beyond the annotation set.

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 sentences, each carrying distinct load: purpose, pricing/negotiation rule, escrow consequence, and pre-call/counter-offer instructions. Front-loaded with the core action and zero filler.

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 mutation tool with no output schema, it covers the transaction lifecycle and the preconditions well. It only lightly implies that deal_id and status_key are returned values the agent must capture, which is the one detail an agent needs to complete the counter-offer loop.

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 only 40%, leaving domain, deal_id, and status_key undocumented in the schema. The description compensates by explaining that deal_id and status_key come 'from the last answer' and are used to respond to a counter-offer, and that amount is confirmed with the user. Only 'domain' is left implicit.

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 ('Offer to buy a domain listed with GoMain') and immediately distinguishes itself from the passive listing/search siblings by describing the transaction path. An agent knows this is the purchasing action, not a search or appraisal tool.

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?

Explains the decision rule (at/above asking buys outright, lower is auto-negotiated up to three rounds), instructs confirmation of amount and email before calling, and tells the agent exactly which condition selects the alternate invocation path (deal_id + status_key to answer a counter-offer). This is explicit when/how guidance.

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