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

Beyond the annotations (non-destructive, non-idempotent create), the description discloses meaningful behavior: brandKitId binds a kit that themes every render, omitting it yields unbranded output, and the tool returns the ProjectResponse. It doesn't state that repeated calls create duplicate projects (the idempotentHint=false implication), but the added brand semantics and return shape are real disclosure.

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-loaded with the purpose, then why it's needed, then parameters, then the brand binding, then the return shape. Dense but each sentence carries information; only mildly long.

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?

With an output schema present and annotations covering safety, the description supplies the missing context an agent needs (purpose, callers, brand binding, return). The only gap is that width, height, and description params are not mentioned, though the schema documents them.

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 semantic value: brandKitId's effect (colors/fonts/motion across renders, sourced from create_brand_kit) and the format sub-fields (aspectRatio/fps/resolution). It omits width/height/description, which the schema covers, so it modestly exceeds baseline.

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 (create a project) and defines what a project is ('the unit you compose and render into'), then names the consuming siblings (compose, apply_composition, create_render, preview family) that require a projectId. An agent can distinguish this from create_brand_kit, create_render, or list_projects without opening any schema.

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?

Explains why/when to call it (any tool needing a projectId requires one to be minted first) and points to update_project for rebinding or changing the brand kit later. There is no explicit 'when not to use' or preconditions, but the motivating context is clear.

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