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

Annotations already declare the safety profile (readOnly, idempotent, non-destructive, openWorld), so the bar is lower, yet the description adds genuinely new context: the credit cost ('1 point per returned record') and the shape of returned records. It does not mention pagination behavior across start_page.

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 the resource and input mode front-loaded; nothing is wasted and it stays well within a single glance.

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 read-only list tool with full parameter coverage and clear annotations, the description is nearly sufficient. It omits guidance on the start_page/max_items pagination relationship and how to page deeper, but with no output schema the listed return fields partly compensate.

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 username/URL input, domain enum, max_items cap, and start_page. The description's 'by username or URL' merely restates what the schema says, adding no syntax or format detail beyond it.

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-resource pairing ('Followers of a Poshmark closet') and the input mode ('by username or URL'), and even names the returned fields (handle, name, avatar). It implicitly distinguishes from the sibling run_poshmark_users_following by using 'followers', but it never names the alternative explicitly.

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 phrase 'by username or URL' implicitly tells the agent what input is expected, and the resource is clear, but there is no explicit when-to-use/when-not guidance and no reference to sibling tools like run_poshmark_users_following that an agent could confuse this with.

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