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

Annotations already declare readOnly, idempotent, non-destructive and openWorld, so the safety profile is covered. The description adds one genuinely useful non-annotation fact, the credit cost ('1 point per returned record'), but says nothing about pagination behavior or how results are ordered by default.

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 front-loaded sentences: the primary identity of the tool comes first, the billing note second. The filter enumeration is somewhat redundant with the schema's property names, but the whole thing is short and earns most of its space.

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 16-parameter tool with no output schema, the description leaves the return shape largely unexplained beyond the point-cost note. It never characterizes a 'record' or indicates pagination/ordering, so an agent knows how to call it but not what to expect back.

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% with 6 enum parameters, so the schema carries all filter syntax, enumerations and defaults. The description's list of filter dimensions (department, category, brand, size, color, price, condition, shipping, availability, sort) merely restates the parameter set without adding format or semantics.

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 description states a specific verb and resource ('Listings in a Poshmark closet') and scopes it to a lookup key ('by username or URL'), which separates it from run_poshmark_items_search and run_poshmark_users. It does not explicitly name the sibling tools, but the closet-scoped framing is clear.

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?

Usage is implied by the scoping phrase 'by username or URL', which tells the agent this is the tool for enumerating one user's listings. However, it never states when to prefer this over run_poshmark_items_search, run_poshmark_items, or run_poshmark_users, nor any prerequisites or exclusions.

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