Export a pixel art canvas to a PNG file. Specify the output filename and optionally choose a canvas to save.
Export a canvas to a PNG file.
| Name | Required | Description | Default |
|---|---|---|---|
| canvas | No | Canvas name | default |
| filename | Yes | Output filename (e.g. hero.png). Saved to --export-dir or CWD. |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full burden, but it only restates the purpose. It does not mention side effects such as file creation, overwriting behavior, or failure modes when the canvas doesn't exist, leaving the tool's behavior largely undisclosed.
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 a single, efficient sentence with no filler. It is front-loaded with the core action and output format, making it easy to parse quickly.
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 tool is simple and the schema covers parameters, but without annotations or behavioral details the description provides only minimal context. Missing information like overwrite behavior or error conditions means it is adequate but not 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 the schema already fully documents both parameters (canvas name and output filename). The description adds no extra parameter meaning beyond the schema, warranting the baseline score of 3.
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 uses a specific verb and resource: 'Export a canvas to a PNG file.' This makes the tool's primary operation clear. However, it does not explicitly contrast with siblings like create_canvas or draw_line, so it misses the top score for sibling differentiation.
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?
No guidance is given about when to choose export_png over other canvas tools, nor any exclusions or conditions. The description simply states the action without contextual usage advice.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.