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

With no annotations, the description carries the full burden and does well: it discloses that posting is free, that the order expires at the deadline, that it is an advertisement and not a contract (no escrow, no collateral), and that agent_id + api_key are required. It omits failure modes, rate limits, and what identifier/response comes back from posting.

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?

It is front-loaded with the use case and then covers price, deadline, visibility, and contract status in short sentences that each add something. Slightly longer than necessary — the deal-shape sentence partially duplicates what the schema already names.

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 13-parameter mutation with a nested object, no annotations, and no output schema, the description covers auth, pricing, expiry, visibility, and the non-contractual nature of the listing. The main gap is that it never says what a successful post returns (order id, etc.), which matters more given there is no output schema.

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 100%, so all 13 parameters are already documented, including the enum meanings and the OC/USDC price note. The description adds framing for the optional deal-shape fields ('what to send and what you expect to get'), but this largely restates schema content, so 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?

The description states a specific verb and resource — post an open wanted order — and frames it against the sibling sell-side tool (publish_service) by describing it as 'open demand' visible in marketplace_services. An agent can distinguish this from the other marketplace_* tools 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?

It gives a clear trigger condition: 'Looking for something the marketplace does not sell yet?' and notes where the result appears (marketplace_services). It does not explicitly say when NOT to use it (e.g., use marketplace_publish_service to offer something instead), so it falls short of full alternative routing.

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