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

With no annotations provided, the description carries the full burden of explaining behavior. It explains the basic effect (1px border) and mode differences, but omits details such as whether the operation is destructive, permissions needed, or how it interacts with transparency. The description is adequate but lacks depth.

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 concise, consisting of two sentences. It front-loads the main action and provides essential details without extraneous information.

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?

Given the tool has 9 parameters including nested objects and no output schema, the description is too sparse. It does not explain the region parameter, clip behavior, or return format. Essential context for proper usage 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?

The input schema has 89% description coverage, so the baseline is 3. The description adds value by explaining the 'mode' parameter ('outside' draws into transparent pixels; 'inside' onto the shape's edge). Other parameters like clip, region, etc., are not elaborated beyond what the schema provides.

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 tool draws a 1px border around non-transparent pixels, specifying two modes ('outside' and 'inside'). It distinguishes the tool's action with a specific verb and resource, and differentiates between the mode options.

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 provides no guidance on when to use this tool versus alternatives like line, rect, or ellipse. It does not mention scenarios, prerequisites, or when not to use it.

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