set_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. It only states the action ('sets') without disclosing side effects, overwrite behavior, canvas existence requirements, bounds validation, or error handling. For a mutation tool with zero annotation coverage, this is insufficient detail beyond the bare operation.

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, clear sentence with no wasted words. It front-loads the core action and resource while briefly mentioning the supported color formats. This is appropriately concise and structured.

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 the description omits any mention of prerequisites (e.g., canvas must exist), side effects, or error behavior. While the operation is straightforward, the lack of annotations makes the description thin. It is adequate but could be more complete by noting what happens if coordinates are out of bounds or the canvas is missing.

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 all four parameters. The description adds no additional meaning beyond what the schema provides – it merely restates that color can be a hex or palette index, which is already in the parameter description. Baseline 3 is appropriate since the schema does the heavy lifting.

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 verb 'Sets' and the resource 'a single pixel at (x, y)' with a hex color or palette index. It distinguishes itself from siblings like set_pixel_batch by explicitly indicating 'single pixel', making its scope unambiguous without needing to open the schema.

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 usage for setting one pixel at a time, but does not explicitly mention alternatives or conditions for choosing this over set_pixel_batch, draw_shape, or flood_fill. The context is clear (single pixel operation) but lacks explicit guidance on when not to use it or which sibling to prefer.

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