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

Goes well beyond the destructiveHint/readOnlyHint annotations: accepting starts the sale and updates the listing, and a counter mutates the listing for every buyer, not just this one. It also discloses the payout-only pricing model and the meaning of the confirmation gate, which are exactly the consequences an agent needs.

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?

Front-loaded with the action and resource, then the payout-model caveat, then the consequences, then the confirmation rule — every sentence carries decision-relevant information with no 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 destructive mutation tool with no output schema, it covers safety consequences, pricing semantics, and confirmation adequately. It stops short of stating what happens to competing offers when one is accepted, which is a real open question for the agent.

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?

With 50% schema coverage, the description adds meaningful semantics: counter_payout_usd is the seller's net payout and Commonplace derives the buyer price, and `confirmed` gates real mutation. The enum values for `action` are self-explanatory in the schema, so full marks aren't warranted.

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 specific verbs (accept, counter, decline) and the resource (an open offer on the seller's own listing), which cleanly separates it from seller_list_offers (read) and listing_update (edit). An agent can pick this tool 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?

Explains the operating context (seller works in PAYOUTS, counter is expressed as counter_payout_usd) and the prerequisite that `confirmed: true` is only sent after the seller agrees. It does not explicitly name alternatives or say when not to use it, but the preconditions are clear.

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