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

Annotations only tell the agent this is a non-read-only, non-destructive write; the description carries the real burden and does so: seller rules auto-agree or auto-counter, an opening offer at the limit often pays the limit, and a new owner_key is minted on the first call. The approval_url handoff to the person is a behavioral detail no annotation or schema field conveys.

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 action and its constraints are front-loaded, and each sentence carries usable information rather than restating the name. It is slightly dense and run-on, with several clauses chained by semicolons, but no sentence is clearly disposable.

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 10 parameters and an output schema present, the description correctly focuses on process rather than return values, while still naming the salient answer fields (next_action, approval_url). It leaves unstated what happens on an outright rejection or a seller who never responds, which matters for an offer that may sit open.

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; the description earns above that by explaining the intent behind person_wants and person_max_usd (both shown to the person beside the deal before approving) and the constraint linking price_usd to person_max_usd. It doesn't add anything for delivery, must_haves, note, or agent_label beyond what the schema already says.

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 first sentence names a specific verb and resource ('Offer a price on a listing') and the beneficiary ('for the person'), immediately distinguishing it from market_counter and market_accept. The negotiation flow described makes it clear this is the entry point of a bargaining sequence, not an acceptance.

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?

Explicit conditional routing: omit owner_key on the first call, call market_counter when next_action is counter_again, send approval_url once the price is agreed. It also gives a concrete behavioral rule ('never offer above the person's limit') and the rationale for opening low.

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