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

Annotations only declare readOnlyHint=false and destructiveHint=false; the description goes further by explaining that total price is computed automatically (quantity × pricePerUnit), that the result carries 'pending' status, and that an on-chain escrow can optionally be linked. It still omits auth/permission requirements, but adds real behavioral value beyond annotations.

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, the core action front-loaded and each sentence carrying distinct information (action, pricing/return behavior, escrow option). 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 mutation tool with no output schema, the description covers the key outcome (order returned with 'pending' status) and the optional escrow path. Only missing pieces are permission/auth expectations and whether repeated calls create duplicate orders.

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 the schema already documents all four parameters. The description adds the quantity×pricePerUnit relationship and frames escrowAddress as optional, but offers no syntax or format detail beyond the schema, 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?

Specific verb (Place) plus resource (purchase order for supplies/materials), clearly distinct from sibling read tools like marketplace_get_order and marketplace_list_orders. An agent can identify it as the order-creation 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?

No statement of when to use this versus marketplace_get_order/marketplace_list_orders, and no prerequisites such as the listing needing to exist or quantity constraints. Usage is only implied by the verb.

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