canvas_set_background

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

No annotations are provided, so the description carries the full burden. It discloses the mutation (setting background color or alpha transparency) but does not say whether it overwrites an existing background, whether it is undoable, or what permissions/state it requires.

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 core purpose sentence is front-loaded and tight, but the second sentence is a long, promotionally-toned NOTE that is mostly about other tools rather than this one. It has routing value for AI designers, yet it inflates the definition considerably.

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 two-parameter tool with full schema coverage and no output schema or annotations, the description covers the essential ground and adds cross-tool routing. Only the lack of overwrite/undo behavior keeps it from being fully complete.

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%, so both parameters are already documented with hex format and boolean semantics. The description's phrase 'solid background color or enables alpha transparency' loosely maps to color/isTransparent but adds no format or constraint detail beyond the schema.

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 ('Sets the solid background color or enables alpha transparency'), which cleanly separates it from the sibling tools canvas_set_gradient and canvas_set_pattern. An agent can tell immediately what this tool governs.

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?

Explicitly routes the agent away from this tool when a richer background is desired, naming concrete alternatives (image_add with { isBackground: true }, assets_list_patterns, assets_list_stock_pngs, assets_list_local). It gives clear context for selection but never states when this tool is the required choice over those alternatives.

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