rect

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

With no annotations provided, the description must carry the full burden of behavioral disclosure. It only states the basic drawing action without mentioning side effects, coordinate conventions, transparency, or whether the rectangle overwrites existing content. The outline default and color format are absent from the description.

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 that clearly states the action and the outline/filled option. It is concise with no extraneous words. However, it is slightly under-specified for a tool with this many parameters, which slightly reduces the score.

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 tool with 7 parameters, no annotations, and no output schema, this description is far too sparse. It provides no usage example, no return value, and does not clarify the role of canvas_id or the default outline behavior. The schema covers parameter names, but the overall context for using the tool is incomplete.

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 baseline is 3. The description adds no additional parameter meaning beyond the schema, which already thoroughly documents each parameter such as 'Top-left X', 'Width', and 'Hex char 0-F or '.' for transparent'. There is no extra value from the tool description.

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 ('Draw'), the resource ('a rectangle on a canvas'), and the dual scope ('outline or filled'). This strongly distinguishes it from sibling tools like 'line' and 'pixel', which draw different shapes.

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 provided on when to use this tool versus alternatives. It does not explain when an outline or filled rectangle is appropriate, nor how to choose between 'rect' and 'fill' or 'line'. This lack of context may lead to incorrect tool selection.

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