annotate_screenshot

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

With no annotations provided, the description carries full burden. It discloses side effects (copy to clipboard, show to user), return value (marked image), and coordinate system constraints, leaving no ambiguity about what happens.

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?

Well-structured and appropriately sized. Each sentence contributes unique information: action statement, prerequisite, coordinate example, per-shape semantics, and return value. No redundancy or filler.

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?

Despite no output schema and no annotations, the description provides complete context for a complex parameterized tool. It covers prerequisites, coordinate system, shape-specific usage, and return value, making it fully self-sufficient.

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?

Description adds significant value beyond schema by explaining fractions 0..1 with top-left origin, shape-specific point semantics (rectangle/ellipse opposite corners, arrow start/tip, pen/highlight run of points). These details are absent from the schema descriptions.

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 on a screenshot, copies to clipboard, and shows to user. It distinguishes itself from sibling take_screenshot by explicitly referencing it as a prerequisite.

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?

Explicitly instructs to call take_screenshot first and LOOK at the image before drawing, providing a clear when-to-use and workflow. No alternatives mentioned, but the step-by-step guidance is sufficient.

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