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

With no annotations, the description carries the burden and does well: it discloses the sale price rule, the equip/attune prerequisite, and the non-idempotency with its failure mode ("a blind retry after a timeout can sell twice"). It stops short of covering error behavior (unknown itemName, insufficient quantity) or what a successful call returns.

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?

Three sentences, zero filler, and the highest-risk fact sequence (price → prerequisite → retry hazard) is front-loaded so a skimming agent still catches the non-idempotency.

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?

No output schema exists, yet the description never says what comes back on success (gold received, item removed, partial-sale behavior for qty > 1). Everything else an agent needs — prerequisite, price, retry policy — is covered, so only the return contract is 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 coverage is 100%, so the schema already documents tableId, characterId, itemName and the qty default. The description adds no syntax, format, or edge-case meaning beyond pointing at ad_get_shop for item names, so the baseline 3 applies.

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?

Specific verb+resource ("Sell an owned item to the merchant") with scope ("where the party stands") and price rule ("half the book price"). It is clearly the inverse of the sibling ad_buy_item, so an agent can distinguish it without opening a 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?

States a hard precondition ("Equipped or attuned items must be unequipped/unattuned first") and names the sibling to use on an uncertain result ("re-read the shop with ad_get_shop first"). Both when/when-not and the alternative are explicit.

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