canvas_create_image

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

Annotations already indicate non-readOnly (false), non-destructive, and open-world. The description adds critical post-processing behavior: always open generated images in Preview. However, it lacks details on cost implications or additional side effects, which would further enhance transparency.

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 well-structured with clear sections: intro, usage guidance, exclusion list, important note, and examples. Every sentence serves a purpose, and it is front-loaded with the core function. Highly concise with zero waste.

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?

Given the tool's complexity, the description covers modes, usage, and post-processing. The output schema exists, so return values are covered. However, it omits mention of the spend_authorization parameter and potential cost implications, which are relevant for an image generation tool.

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 0%, but the schema itself has rich property descriptions. The tool description compensates by explaining the plan-based vs direct usage distinction via examples, adding meaning beyond the schema. Yet it does not describe all parameters individually, though the schema covers them.

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 clearly states the tool's function: generating marketing images with two modes (plan-based or direct). It explicitly distinguishes from sibling tools by listing what not to use (canvas_render_layout, canvas_edit_image, canvas_inspect_asset), making its purpose unambiguous.

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 provides explicit guidance on when to use each mode (plan-based for complex jobs, direct for quick one-shot) and when not to use the tool, with references to alternative sibling tools. This fully informs the agent on appropriate usage.

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