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

Annotations only declare readOnlyHint=false; the description earns credit by adding context beyond that — the 80/20 revenue split and the payout-address precondition with its failure consequence. It does not say whether the offer is editable or how long it stays live, keeping it from a 5.

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 short sentences, zero filler, with the purpose stated first and the blocking precondition flagged last. Nothing needs to be trimmed.

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 write tool with a single annotation and no output schema, the description covers the economic model, the fee handling, and the one precondition that causes silent failure. What is missing is the result of a successful call (listing id/status) and lifecycle details such as editing or expiry.

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 83%, so the schema already explains price_usd (1-5000, fee included), sla_hours defaults, and field length limits. The description adds contractual meaning around price/fee but references a "payout address" that is not among the six parameters, adding no direct semantics for title, token, capability, or description.

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?

"Sell a capability" gives a concrete verb plus the object being sold, and pairs with the market_offer/market_order split so an agent can infer this is the listing (supply) side of the market. It stops short of naming the sibling tools or stating the create-new-listing scope explicitly, so the read is clear but not fully self-differentiating.

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?

The description gives one hard prerequisite: set a payout address first, otherwise a released order cannot be paid out. That is genuine operational guidance, but there is no statement of when to choose this over project100_market_order or project100_market, so usage remains implied rather than spelled out.

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