canvas_plan_image

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

The description explains the two actions (plan and approve) and mentions that planning returns a CreativePlan with plan_id and status. It also notes that planning is a prerequisite for generation. While annotations already indicate the tool is not read-only and not destructive, the description adds context about the multi-step workflow. It does not fully detail side effects or rate limits, but it is sufficient for the tool's purpose.

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, well-organized, and front-loads the main purpose. It uses bullet points for use/not-use, a numbered list for actions, and an example. Every sentence adds value with no redundancy or extraneous information.

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?

The description covers the dual-mode operation and gives a concrete example, which is sufficient for most users. It mentions the return of a CreativePlan but lacks details on the output structure (no output schema in the tool definition). Additional context on error handling or edge cases would improve completeness, but the description is reasonably complete for a planning 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?

Context signals indicate schema description coverage is 0%, requiring the description to compensate. The description provides a usage example that illustrates key parameters (goal, subject_type, reference_image) and their roles, but does not explain all 15+ parameters. The schema itself contains descriptions for each parameter, which offsets some of the burden, but the description could be more thorough in explaining parameter interactions.

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 that the tool is for planning and validating creative requests before generation. It explicitly distinguishes from siblings by listing use and do-not-use cases, such as using canvas_create_image for quick one-shot generation, and names alternative tools. The verb 'Plan and validate' is specific and the resource 'creative request' is well-defined.

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 includes a dedicated 'Use when' section specifying when to preview costs, workflow, and fidelity, and a 'Do not use when' section with explicit alternatives (canvas_create_image, canvas_render_layout, etc.). This provides clear, actionable guidance for tool selection.

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