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

Goes well beyond the annotations: ~2 minute runtime, credits are spent at the same rate as the website, approval_required pauses everything until the person answers in the PrismPoster card or link, output lands in their library, and requests involving minors or public figures are refused before any charge. These are exactly the side-effect and safety facts an agent needs for a credit-spending mutation.

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?

Front-loads what gets produced, then layers cost, approval, and policy. Every sentence carries information, though the closing sentences are long chained clauses that could be split for faster scanning.

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?

For a fixed-price, credit-spending generation tool with no output schema, the description covers outcome, cost, timing, approval gating, refusal policy, and where results are stored. The only unstated detail is the exact return payload (job id), which get_job and the approval_required flow already imply.

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?

With 50% schema coverage, the description compensates by enumerating the optional attributes (age, hair, eye colour, clothing, height, personality) that the undescribed enum parameters carry, and it explains the naming/@tag mechanic behind `name`. It leaves `approval_id` and `idempotency_key` to their schema descriptions, which already document them adequately.

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 (design a character sheet with full-body turnaround views and an expression grid) and explains the outcome — visual consistency across later images and videos. That clearly separates it from create_image, edit_image, and preview_remake_cast without requiring the sibling schemas to be opened.

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 concrete usage context: describe freely, optionally pin age/hair/eyes/clothing/height/personality, and name it to get an @tag for later prompts or Remake casting. It also points to quote_job for a free price check before spending. It never explicitly says when NOT to use it (e.g. use create_image for a one-off picture of an existing subject), so it stops short of full alternative routing.

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