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

Annotations already declare readOnly, idempotent and non-destructive, so the safety profile is covered. The description adds genuinely useful context beyond that: links are private and signed, another read refreshes them, and no charge or processing is repeated on re-read.

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 compact sentences, front-loaded with what is returned before the link/signing caveats. No filler sentences; each clause carries information.

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 an output schema present and rich annotations, the description need not explain return values, and it covers the remaining gaps (signing, link expiry, polling behavior, no re-charge). Complete enough for a result-fetch tool, missing only explicit sibling routing.

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 the single parameter is fully documented, so the schema does the heavy lifting (baseline 3). The description only adds that the quoteId must be 'approved', a modest clarification.

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 (Returns) and resource (the owned picture for an approved quoteId), plus enumerates the payload (image.url, downloadUrl, gallery-widget data) and the alternate 'current progress' case. The workflow dependency on an approved quoteId implicitly separates it from studio_image_quote/studio_image_confirm, though those siblings are never named.

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 'once ready, or its current progress' implies polling, and 'No processing or charge is repeated' hints that re-reading is safe. However, it never states when to call this versus studio_image_quote, studio_image_confirm, or studio_generation_status, so routing is left to inference.

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