create_character_pro_flash

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

No annotations are provided, so the description carries the full burden. It discloses that the first image is paid, that pixels are preserved and padded with transparency to the square v3 canvas, that the provider does not promise deterministic output (in the seed param), and that the call returns a job plus character_id. It does not mention rate limits or failure modes, but for a creation tool the key behavioral traits (cost, pixel handling, async job) are covered.

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 dense but well-structured: it front-loads the core purpose, then the cost-saving alternative, then pixel behavior, then the return/polling flow. Every sentence earns its place, though the density of the first sentence is slightly high.

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 complex 12-parameter tool with nested objects and no output schema, the description covers the workflow, the cost model, the mutual exclusivity of image sources, and the follow-up calls. It does not enumerate all parameter semantics (the schema does that), and it doesn't describe the job response shape, but the essential context for correct invocation is present.

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 100%, so the schema already documents all 12 parameters. The description adds value by explaining the relationship between source_image_id, first_frame, and description (mutual exclusivity, still-required description), and by clarifying the paid-image skip path. It also explains the style_image 'left-box' concept and the native canvas constraint, which goes beyond the schema.

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 ('Create'), a specific resource ('saved character'), and a specific engine ('Pro Flash'), and clearly distinguishes the one-call workflow (south-facing image + eight v3 rotation views) from alternatives. It also names the sibling create_image_pro_flash and get_character, so an agent can tell this tool apart from related tools without opening schemas.

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 explicitly explains when to use this tool (one-call character creation with Pro Flash), and when to use alternatives: pass source_image_id from an earlier create_image_pro_flash result or upload first_frame directly to skip the paid first image. It also tells the agent to poll get_job_status and then get_character, which is clear workflow guidance.

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