art.canvas.get_pixel

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. 'Read' does imply a non-destructive operation, but the description is silent on what happens with out-of-bounds or negative coordinates (the schema permits coordinates down to -9007199254740991), how the color is returned (format?), and whether this triggers any validation or session side effects.

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?

One short sentence front-loads the essential message with zero waste. Every word earns its place, and the read-vs-write distinction is immediately visible.

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?

There is no output schema, so the description must explain the return value, but it never states the color format (RGB/hex/RGBA?) or any error behavior. The enormous coordinate min/max in the schema without any clarification about canvas bounds or negative coordinates leaves an agent guessing about valid inputs. For a three-parameter, no-output-schema tool under a large canvas-family context, these gaps matter.

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 coverage is 100%, so the input schema already documents x, y, and session_id. The description adds no coordinate-system context (origin location, valid bounds, units) beyond the schema's extremely wide integer range, which is not meaningful guidance for actual canvas dimensions. Per the high-coverage baseline, a 3 is appropriate.

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 names a specific verb ('Read'), a specific resource ('the color of a single pixel'), and a location ('the canvas'). This clearly contrasts with sibling tools like art.canvas.set_pixel (write) and art.canvas.fill/draw_rect (bulk drawing), so an agent can accurately select it without inspecting any other definitions.

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 on when to use this tool versus alternatives, and no alternatives are named. It does not mention related read operations such as art.canvas.get_state or art.analyze_ref, nor does it advise against using it for batch reads. The intended context is implied but never stated.

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