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

The annotations already declare readOnlyHint=true, so the description does not need to restate that this is a safe, non-mutating operation. The description adds value by specifying the output (status and fresh image URLs), which is not covered by the annotation. However, it does not disclose potential error behavior, rate limits, or any other behavioral nuances beyond the basic return content.

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?

The description is a single, front-loaded sentence with no filler. It conveys the action, the resource, and the output in a concise manner. Every word earns its place, and it is immediately scannable by an agent.

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?

The tool has only one input parameter and no output schema, yet the description communicates the essential return values (status and fresh image URLs). It does not detail the structure of the status or the URL format, but these are likely evident from the response itself. The description is adequate for a simple getter; it does not leave the agent guessing about the purpose or the primary output.

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 0%, so the description must compensate for parameter meaning. It explicitly identifies the parameter as a 'generation id', which clarifies that the 'id' field is the identifier of a generation. This goes beyond what the schema provides (only type and format). For a single parameter, this is sufficient and more than minimal.

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 verb ('Returns') and a specific resource ('generation id'), and clarifies what is returned: status and fresh image URLs. This clearly differentiates from siblings like account_usage (usage stats), generate_thumbnails (creates media), and list_models (lists available models). No ambiguity about the tool's function.

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 description implies that this tool is used when you have a generation id and need its status or image URLs, but it does not explicitly state when to use it over alternatives or any exclusion criteria. Since the tool is a straightforward getter, the usage is inferable from the name and description, but there is no explicit guidance.

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