Create a named canvas with specified pixel dimensions. Reuse a canvas name to replace an existing one, enabling programmatic pixel art setup.
Create a new named canvas with given dimensions. If a canvas with this name exists, it is replaced.
| Name | Required | Description | Default |
|---|---|---|---|
| name | No | Canvas name | default |
| width | Yes | Width in pixels | |
| height | Yes | Height in pixels |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the burden of behavioral disclosure. It explicitly reveals the key destructive behavior: 'If a canvas with this name exists, it is replaced.' This is important because an agent might otherwise assume creation fails when the name is taken. It could also mention return behavior, but the replacement semantics are the most critical behavioral trait and are clearly disclosed.
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 two sentences with no filler. The primary purpose is front-loaded, and the critical replacement behavior is stated immediately after. Every sentence earns its place.
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 simple create/replace tool with a fully documented schema and no output schema, the description covers the essential behavior. The main missing element is explicit guidance about when to use this tool relative to the siblings, but the creation and replacement semantics are sufficient for correct invocation in most cases.
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 the schema already documents name, width, and height with defaults and constraints. The description only restates the concepts of 'named' and 'dimensions' without adding new meaning, such as how width/height interact with replacement or coordinate origin. This matches the baseline for full schema coverage.
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 action ('Create a new named canvas') and the resource, and adds a precise scoping detail: dimensions and name. It also distinguishes itself from sibling tools by emphasizing named canvas creation and replacement, so there is no confusion with list_canvases, set_pixel, or drawing operations.
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 implies that this tool is for initializing or replacing a canvas by name, but it does not explicitly state when to use it versus alternatives, nor does it mention prerequisites or exclusions. For example, it does not say to check list_canvases first or to use clear/undo for resetting content within an existing canvas.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.