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

Goes well beyond the annotations by disclosing the destructive consequence ('The listing comes down'), the auth profile ('No account is required'), a failure edge case ('If it never published, the confirm link stops working'), and the token provenance from listing_crosslist_draft. These are exactly the behavioral facts an agent cannot derive from destructiveHint/idempotentHint alone.

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?

Short, front-loaded sentences that lead with the usage trigger before the mechanics, with zero filler. It does repeat the Facebook Marketplace / Craigslist / OfferUp list twice, which is minor redundancy in an otherwise tight block.

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 one-parameter, no-output-schema tool, the description covers trigger, dependency, auth, destructive effect, and an edge case, so an agent has everything needed to call it. The reference to a 'confirm link' is left slightly unexplained (who holds it, what it is), which is a small residual 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 100% and the single parameter is documented in the schema, so the baseline is 3. The description adds genuine value by stating the token must be the one returned by listing_crosslist_draft, establishing provenance the schema's generic 'returned with the draft' wording does not.

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 ('mark sold') and the exact trigger condition—the item sold on Facebook Marketplace, Craigslist, OfferUp, or anywhere else—plus the concrete effect ('The listing comes down'). This distinguishes it from siblings like seller_remove_listing or seller_relist_listing, which do not carry the 'sold elsewhere' semantics.

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?

Explicitly says when to call it ('Use when the user is selling a large or valuable item... Call this when the item sells on Facebook Marketplace, Craigslist, OfferUp, or anywhere else') and names listing_crosslist_draft as the source of the required token. It does not, however, state when NOT to use it versus seller_remove_listing or seller_relist_listing, so an agent facing an ambiguous removal scenario still has to infer.

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