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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), and the description adds genuinely new operational context: free, never 402, no preview quota consumed, and that the verdict is advisory because inspect re-checks. It does not describe the failure shape (what a dirty zip returns), which is the main remaining gap.

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 dense sentences, front-loaded with purpose before the quota/alternative rationale. Every clause carries actionable information (cost behavior, workflow loop, sibling routing, advisory semantics) with no filler.

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 one simple parameter, full schema coverage, and no output schema, the description supplies what the structured fields cannot: cost/quota behavior, the advisory nature of the verdict, and how it composes with inspect and upload_url. Nothing needed to call this correctly 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% and there is a single required parameter, so the schema already explains uploadId fully. The description reinforces the provenance ('the uploaded zip', 'upload_url again') but adds no syntax or format detail, so baseline 3 applies.

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 ('Check an uploaded zip for unsafe files') and immediately bounds the scope with 'WITHOUT deploying anything'. This clearly separates it from inspect, which deploys a preview Worker, so an agent can discriminate among siblings without opening any schema.

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?

Explicitly prescribes the iteration loop (scan → fix → upload_url again → scan) and names the alternative ('call inspect to deploy a throwaway preview Worker') with the condition that selects it ('when the content is clean and the human wants to SEE it'). It also frames the verdict's role in that workflow.

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