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

The description discloses that the call is free, never starts a generation, and returns exact account prices, prompts, budget guidance, and output checks. This is consistent with the readOnlyHint and idempotentHint annotations, adding practical detail about what the agent will receive without contradicting the annotations.

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 concise, with three sentences covering purpose, return value, cost, and usage timing. It is well-structured and free of redundancy, making it easy for an agent to parse quickly.

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?

Despite having no output schema, the description sufficiently informs the agent of what to expect (prices, prompts, budget guidance, output checks) and references related tools like list_models for duration validity. This is complete enough for correct selection and invocation.

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?

All six parameters have clear descriptions. For example, max_credits explains the full budget scope, retries included, and the STOP behavior; video_model explains the fallback logic; image_url explains the behavior when absent. Schema coverage is 100% and each description adds meaningful context.

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 explicitly states the tool's purpose: to plan a complete product-photo workflow, returning prices, prompts, budget guidance, and output checks. It clearly distinguishes its role from generation tools by instructing to use it before making product ads or videos and noting it never starts a generation.

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?

It provides explicit usage guidance: 'Use before making product ads or product videos.' It also clarifies cost behavior ('Free: never starts a generation') and describes how budget and model selection are handled, steering agents to this planning step before invoking sibling generation tools.

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