pixel_resize_canvas

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

The description fully discloses behavior: existing art is unchanged, new space is transparent, anchor determines placement, and it explains the return format including JSON and preview image. Annotations already indicate destructiveHint=true, but the description adds valuable context about what exactly happens.

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 concise, using four sentences to convey all key information. It front-loads the core purpose and includes an example and return format without unnecessary words.

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 no output schema, the description fully explains the return JSON structure and error handling. It covers all necessary behavioral aspects for an agent to use it 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 input schema already has descriptions for all parameters, so the description's role is lighter. However, the description adds practical context (e.g., anchor='bottom' keeps feet planted, preview returns rendered image). This adds value beyond the schema definitions.

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 it changes canvas bounds without scaling art, using a specific verb and resource. It distinguishes itself from the sibling pixel_scale_canvas by explicitly noting that pixel sizes are unchanged, making the purpose highly specific.

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 clear context for when to use this tool (grow or crop canvas) and explicitly points to pixel_scale_canvas as an alternative for rescaling art. It also gives a concrete example with anchor. However, it does not explicitly state when not to use it beyond the mentioned alternative.

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