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

With no annotations, the description must carry the behavioral load, and it does disclose meaningful traits: the output is a public address, the result is attached to this tool's row, and the call consumes one image allowance with 'best' costing roughly 5x. It omits auth/permission requirements and whether the asset persists or can be regenerated/replaced.

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 and followed by output/downstream behavior and cost. Every sentence carries information, though the semicolon-heavy middle sentence packs return value, consumers, and UI placement together, which is slightly heavy for one breath.

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 output schema exists, and the description compensates by explaining the returned public address and how it is consumed downstream, plus the allowance cost. For a 3-parameter tool with full schema coverage this is sufficient, with only persistence/auth details left unstated.

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 100%, so the baseline is 3, but the description adds real semantics beyond the schema by quantifying the cost of quality='best' and constraining its use. Aspect ratio meaning is already well covered in the schema, so the marginal gain is moderate rather than large.

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 concrete verb+resource ('Make one picture from a description') and enumerates representative outputs (product shot, social visual, hero art, ad creative). The word 'picture' plus the aspect-ratio examples cleanly separate it from the sibling generate_video.

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 a clear condition for the expensive path ('quality best ... use it only when asked') and names the downstream consumers (write_landing_page, write_email_template), which tells the agent when the result is worth generating. It never states when NOT to use this tool or when to prefer generate_video/an alternative.

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