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

Annotations declare readOnlyHint=false and destructiveHint=false, consistent with a create operation. However the description adds no behavior beyond that: no auth/role requirements, no statement of what the created listing returns or where it appears, no side effects such as inventory or seller state changes.

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?

Two sentences, zero waste, with the core action front-loaded before the clarifying domain context. Every sentence earns its place.

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 12-parameter mutation tool with no output schema, the description is minimally adequate: it says what is created but omits prerequisites, the seller identity requirement, and any post-creation behavior. The rich schema compensates on parameters, but the description leaves real gaps for a write operation.

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 12 parameters (including the category enumeration values) are already fully documented in the schema. The description's mention of material types mirrors the category field but adds no syntax, constraints, or meaning beyond the schema. 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?

States a specific verb+resource ('Create a new supplies/materials listing in the marketplace') and scopes the domain with concrete examples (raw materials, lab reagents, tooling, consumables). An agent can distinguish this write operation from the marketplace_get/update/delete/list siblings 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?

The description implies when to use it (posting supplies for others to purchase) but never names the alternative siblings (marketplace_update_listing, marketplace_place_order) or states prerequisites such as needing a sellerId or registering first. No explicit when/when-not guidance.

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