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

With no annotations, the description carries the full behavioral burden. It usefully discloses the return fields and a per-record cost, which is real behavioral context an agent needs. However, it says nothing about pagination behavior, whether start_page interacts with max_items, or any rate-limiting, so the disclosure is partial.

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 compact sentences with no filler, and the resource definition is front-loaded. The parenthetical field list and cost note are both worth their space. Only the slightly tangled first clause keeps it from a 5.

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 four-parameter list tool with full schema coverage and no output schema, the description covers what is returned and the per-record cost. Pagination semantics and how start_page pairs with max_items are the remaining gap, but nothing critical to invoking the tool is missing.

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 the schema already documents user, domain, max_items and start_page with defaults and bounds. The description's 'by username or URL' merely restates the schema's user description. Baseline 3 is appropriate 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?

The description states a specific resource and direction: the users a Poshmark closet follows, with the three returned fields parenthesized. The grammar is slightly awkward ('Users a Poshmark closet follows'), and it never names the opposite-direction sibling run_poshmark_users_followers, so an agent must infer the distinction from the name alone.

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?

No when-to-use guidance, no prerequisites, and no explicit routing away from run_poshmark_users_followers or run_poshmark_users. Usage is only implied by the description of what is returned. The cost note ('1 point per returned record') hints at budget-awareness but is not framed as usage advice.

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