screenshot_region

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

With no annotations provided, the description carries full burden but only states the basic action. It doesn't disclose behavioral traits like whether it requires user consent, saves files to disk, returns image data, has rate limits, or affects system state. For a screen capture tool with zero annotation coverage, this is a significant gap.

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, efficient sentence with zero waste. It's front-loaded with the core action and resource, making it immediately scannable and appropriately sized for the tool's complexity.

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 screen capture tool with no annotations and no output schema, the description is incomplete. It doesn't explain what happens after capture (e.g., returns image bytes, saves to file), error conditions, or platform dependencies. Given the sensitivity of screen capture operations, more context is needed.

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 fully documents all four parameters (x, y, width, height). The description adds no parameter-specific information beyond implying rectangular region capture. Baseline 3 is appropriate when 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 action ('capture') and resource ('rectangular region of the screen'), making the purpose immediately understandable. It distinguishes from sibling tools like 'screenshot_fullscreen' and 'screenshot_window' by specifying a region rather than fullscreen or window capture, though it doesn't explicitly name those alternatives.

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 'screenshot_fullscreen' or 'screenshot_window'. It doesn't mention prerequisites (e.g., screen access permissions) or typical use cases (e.g., capturing specific UI elements).

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