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

Annotations already declare readOnly, idempotent, openWorld, and non-destructive, so safety is covered. The description adds real behavioral value: the point cost ('Flat 5 points per successful run') and the scope of returned data ('the likers/comments shown on the page'), hinting results are page-limited rather than exhaustive.

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 filler. The core purpose and returned fields lead, and the cost note is appended compactly. Nothing is wasted or buried.

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?

No output schema exists, but the description compensates by listing the returned field groups and the cost, and annotations carry the safety profile. The only minor gap is the absence of pagination/rate-limit detail, which is not critical for a single-item getter.

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 'item' and 'domain' are already documented with examples and enum options. The description only echoes 'by id or URL' for the item param and says nothing extra about the domain param, which is the expected baseline when the schema does the heavy lifting.

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 ('Get one Poshmark listing by id or URL') and enumerates the returned fields (price, brand, size, colors, category, photos, likes/comments, seller). This clearly separates it from the sibling search/comments/likes/related tools by scope ('one' listing).

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 ('by id or URL' when you already have an identifier) but never names alternatives like run_poshmark_items_search or states when not to use it. Usage is inferable from the singular 'one ... listing' framing, but no explicit routing guidance is given.

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