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

Beyond the annotations it discloses the review gate (new name, category, video, link or a rewrite on a live listing waits for review while drafts change at once), the required scope (listings:write), and per-field clearing behavior — none of which the readOnly/destructive/idempotent hints convey. It also notes the tool is non-idempotent in effect for live listings because of the moderation queue.

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?

Front-loaded with the verb and the field list, then the clearing rule, then slug sourcing, then the review caveat — a sensible priority order in roughly 100 words. The long comma-separated field enumeration partly duplicates the schema and could be trimmed.

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 15-parameter mutation with an output schema and annotations already present, the description covers the remaining gaps an agent needs: auth scope, partial-update and clearing semantics, slug provenance, video host validation, and the draft-vs-live review behavior.

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?

With 93% schema coverage the schema already carries field-level detail, but the description adds cross-cutting meaning the schema does not: which fields are slug-based, that lists are replaced rather than appended, that null/empty clears, and the constraint that links are one per kind. It does not add much on pricingModel or priceFrom beyond the schema.

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?

Opens with a specific verb and resource ("Change any of a listing's details") and enumerates the exact editable fields, so an agent can immediately separate this from draft_listing, submit_listing, or set_listing_cover.

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?

"Send only what changes; null or an empty list clears a field" gives explicit partial-update semantics, and "slugs from get_listing_options" routes the agent to the sibling that supplies valid slugs. It stops short of stating when to prefer draft_listing over editing a live listing, so it is clear context rather than full 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.