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

With no annotations, the description carries full disclosure. It covers async behavior (202 + job id, poll getApiJob with wait: 30), result shape (array with image url and applied rotations), auth requirements (API key user scope), quota limits (50 queued jobs, 429), and credit charging rules (only on success, scaled by generated count).

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?

Although long, every sentence contributes operational guidance: purpose, input constraints, result shape, alternatives, async polling, quota, and credits. It is front-loaded with the core purpose and ends with cost, keeping the critical information near the beginning.

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?

Without an output schema or annotations, this description fully compensates by specifying async workflow, job result structure, auth, rate limits, and success-based pricing. An agent has everything needed to invoke, poll, and interpret the result correctly.

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?

The schema already documents all parameters at 100% coverage, so baseline is 3. The description adds meaning by constraining the image source to sprite types, explaining n as 'number of variations' beyond the raw schema default, and clarifying camera_elevation omission semantics and credit scaling. It does not duplicate every schema field, but adds enough contextual value to earn a 4.

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 ('re-render an existing sprite') with a distinct resource ('sprite') and the goal ('from a different camera viewpoint while keeping the same character and pose'). It clearly differentiates from siblings such as generatePose and animateSprite.

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?

Explicitly says 'Use this to produce alternate view angles of a character' and names alternatives with conditions: use generatePose for pose changes, and animateSprite or transferMotion to bring a sprite to life. It also restricts applicability to sprite image types, giving clear selection criteria.

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