screen_capture

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

With no annotations provided, the description carries full burden. It discloses the core side effect of saving a PNG and returning a path, but omits details such as file location, overwrite behavior, permission requirements, or error handling, which are relevant for a screen capture tool.

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 concise sentence that front-loads the primary action (截屏) and states the output and usage context. Every part adds value without redundancy.

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 simple tool with 2 optional parameters and no output schema, the description covers purpose and regional parameter, but leaves out_path semantics and return-path details vague. It lacks enough detail about the second parameter to be fully complete, though it does provide integration context.

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 coverage is 50%: region has a description in the schema, but out_path does not. The description mentions 'full screen or specified region' for region, but provides no additional meaning for out_path beyond 'saving PNG and returning path', leaving its role ambiguous. It does not fully compensate for the missing schema 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 tool captures a screenshot (截屏) of the full screen or a specific region, saves it as PNG, and returns the path. It also distinguishes itself from sibling analysis/action tools by noting it provides the visual input for locate_object/describe.

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 includes a direct usage context: '配合 locate_object/describe 实现「看屏幕」' indicating it is used in conjunction with those tools to see the screen. It does not explicitly contrast with alternatives or provide exclusions, but the context is clear enough for selection.

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