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

Goes well beyond the annotations (which only declare non-read-only, non-destructive, non-idempotent, closed-world): it discloses that every submission is screened and waits for human owner approval, that nothing is published automatically, that the call is free, and that a duk_ Creator key is mandatory and must never be guessed. These are the operational facts an agent actually needs before invoking a submission endpoint.

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?

Four tight sentences, front-loaded with the action and ownership scope, then prerequisites and moderation behavior. Every sentence carries information; the only mild redundancy is the parenthetical hint on where to find the API key.

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, 8-required mutation tool with no output schema, the description covers the essential unknowns: auth source, cost, moderation/approval flow, and eligibility. It does not describe failure modes or validation behavior for the many undocumented fields, which is the remaining gap.

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 coverage is only 42%, so the description must compensate, and it clarifies api_key (duk_ prefix, Creator dashboard origin) and the accuracy/ownership constraints. But most of the 12 parameters (name, tags, pitchShort, descriptionLong, imageUrl, videoUrl, priceLabel, category) get no added meaning beyond the schema, leaving real gaps.

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 and resource ("Submit the user's own product to the marketplace") plus an ownership scope that separates it from the read-oriented siblings get_listing, get_my_listing_status and search_listings. An agent can tell immediately this is the write path for a creator's own product rather than a lookup.

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?

"Only submit real products the user owns, with accurate claims" gives an explicit eligibility condition, and the API-key prerequisite is spelled out. It stops short of naming the sibling to use for checking status or finding listings, so routing is implied rather than stated.

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