Set a single pixel on a pixel art canvas at specified coordinates with a given color. Enables programmatic pixel-by-pixel image creation.
Set a single pixel on the canvas.
| Name | Required | Description | Default |
|---|---|---|---|
| x | Yes | X coordinate | |
| y | Yes | Y coordinate | |
| color | Yes | Color: #rgb, #rrggbb, #rrggbbaa, or named (red, blue, transparent, etc.) | |
| canvas | No | Canvas name | default |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
There are no annotations to signal safety or side effects, and the description does not disclose behavioral traits beyond the minimal action. It does not state that setting a pixel overwrites existing data, what happens on out-of-bounds coordinates, whether the canvas must already exist, or if undo/redo affects this operation. For a mutating tool, this is a significant gap.
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, front-loaded sentence with zero filler. Every word earns its place, and it delivers the core action and scope immediately. This is ideal conciseness for a simple tool.
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 pixel-setting tool with full schema coverage, the description is minimally adequate to invoke it: an agent can supply x, y, color, and optional canvas. However, there is no mention of coordinate bounds, canvas creation behavior, or failure modes, and no usage alternatives are provided. Given the absence of annotations, a bit more context would make it 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 all four parameters (x, y, color, canvas) already have meaningful descriptions and defaults. The tool description does not add any parameter-level semantics beyond the schema. With high schema coverage, baseline 3 is appropriate even though the description ignores parameter details.
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 ('Set') and identifies the exact resource ('a single pixel') and target ('the canvas'). This clearly distinguishes it from sibling tools like fill_rect, draw_line, and get_pixel, which operate with different shapes or read operations, so an agent can select it confidently.
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 use this tool vs. alternatives. The description only states what it does; it does not mention that fill_rect, draw_line, or get_pixel are better choices for other scenarios. There is no implied 'when-not' or alternative routing, so the agent must infer usage purely from the tool name and sibling list.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.