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

With no annotations, the description carries the burden and does disclose key side effects: character/location/prop creation triggers reference-image generation, style assets do not, and supplying existingMediaUrl skips generation entirely. It does not mention permission requirements, credit/cost implications of image generation, or whether duplicate names are allowed, which are relevant for a creation tool.

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?

Three tight sentences with the purpose front-loaded, followed by the behavioral distinction and the optional-parameter note. Every sentence adds distinct information with no redundancy or filler.

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 12-parameter creation tool with no output schema and no annotations, the description covers the essential behavioral distinctions (image generation vs. text-only, edit.style alternative, existing-media path). The remaining gaps, such as the editId-in-editor requirement and voiceDescription, are already documented in the schema, so the description is largely sufficient.

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% across 12 parameters, so the schema already explains prompt, modelId, editId, and the existingMedia* fields in detail. The description reinforces the prompt and existingMediaUrl semantics but adds little beyond what the schema states; baseline 3 is appropriate when the schema does the heavy lifting.

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 (Create) and resource (asset) and enumerates the four asset subtypes it accepts, which matches the type enum exactly. An agent can distinguish this from siblings like generate_image, create_shot, or create_folder 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?

Gives a clear routing rule for the ambiguous case: style assets do not generate images, and routine projects should store global visual style in edit.style instead. It also clarifies when existingMediaUrl applies (user-supplied reference image). It does not, however, address when to prefer update_asset over create_asset or when an asset belongs in an edit context.

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