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

With no annotations, the description carries the full burden, and it does disclose genuinely useful economics: minimum price, a 9.00 one-time listing fee, free-listing conditions (founder seats, launch week until 11 October 2026, invited sellers) and a per-sale commission (8%, min 0.25; 1% for founders). However, it says nothing about the creation behavior itself — whether the listing goes live immediately or needs review, what happens on validation failure, or whether creation is reversible.

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?

The purpose is front-loaded in a single short clause, but the remainder degenerates into a dense run-on of fee figures and exception dates with nested conditions ('free while... during... and always for...'). It reads like a pricing blurb rather than invocation guidance, and the fee detail crowds out anything about how to call the tool.

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 annotations, no output schema and only 42% schema coverage, the description leaves major gaps: publish/moderation state, required-field behavior, and how delivery/output_schema interact are all unaddressed. It covers the commercial terms but not what an agent needs to call it correctly.

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 only 42% across 12 parameters, so the description is expected to compensate, but it adds nothing about delivery modes, output_schema, reseller_share_pct, mcp_url/mcp_tool or currency. Worse, 'Price from 2.00' conflicts in spirit with the schema's stated range (50–1000000 Rappen, i.e. from 0.50), leaving the actual floor ambiguous.

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 lead clause 'Seller: offer a product or service' states the action and the target audience clearly, and the audience framing helps separate it from get_listing/update_listing/search_listings. It never uses the literal verb 'create a listing', but the resource and intent are unambiguous.

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 identifies the audience ('Seller') and lists fee conditions, but gives no when-to-use guidance relative to alternatives such as update_listing, import_service, shop_add or resell, and no prerequisites for calling it. The agent must infer that this is the entry point for putting an item on the market.

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