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

With no annotations, the description carries the full behavioral burden, and it does disclose one genuinely useful non-schema trait: the operation consumes credits. It leaves everything else undisclosed — whether generation is synchronous, rate limits, or what happens to the existing background. Real but partial value.

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 short, front-loaded sentences with zero filler, and the cost warning sits where a reader will see it. It is efficient, though the terseness edges toward under-specification for a credit-consuming generative tool.

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?

No annotations, no output schema, and 0% parameter coverage mean the description must do all the work, and it does not: no return-value shape, no prompt semantics, no failure/mutation behavior. Inadequate for a two-parameter generative tool.

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% and neither parameter is clarified. 'one card' loosely implies screenshotId identifies the target, but the 'prompt' parameter — which governs the generated output — is never explained, leaving half the parameters undocumented in both schema and description.

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?

Specific verb (Generate) + resource (AI background) + scope ('one card'), which separates it from the project-level sibling set_project_background. It does not, however, distinguish it from the other generation siblings generate_asset and generate_mascot, so sibling differentiation is only partial.

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?

There is no statement of when to use this versus generate_asset, generate_mascot, or set_project_background, and no prerequisites or exclusions. The only guidance is an implicit cost warning ('Spends credits'), which does not route the agent among alternatives.

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