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

Annotations already establish readOnly, idempotent, non-destructive, closed-world behavior, so the description doesn't need to restate safety. It adds genuinely useful context beyond them: 25-row pagination, that the call is free, and the read:results auth requirement.

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?

Three tight sentences that front-load what is returned, then filtering, then cost/auth. No filler or redundancy.

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?

With no output schema, the description carries the return-value burden and discharges it by naming the per-row fields and pagination. Auth scope and cost are also covered, so an agent has everything needed to call it correctly.

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 67% (job_id and verdict documented, page not), so some compensation is expected. The description adds the page size (25/page) that the schema omits, and clarifies verdict filtering with a valid-list example, adding meaning beyond the raw enum.

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 (Fetch) and resource (a bulk job's per-row results), and enumerates the returned fields (email, verdict, risk score, cost). It implicitly separates itself from pingvalid_get_job_status by focusing on per-row results, but never names a sibling explicitly, so it stops short of top-tier differentiation.

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?

Gives one concrete filter example (verdict=valid for the clean list) and states the required read:results scope, which hints at usage context. However, it never says when to prefer this tool over pingvalid_get_job_status or pingvalid_explain_verdict, leaving the alternative selection to inference.

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