appium_screenshot

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

The description discloses a meaningful side effect: the screenshot is saved as a PNG file, which is useful given readOnlyHint=false. However, it does not say where the file is saved, what response shape to expect, or how returnRawBase64 changes the behavior beyond what the schema already states. Some behavioral context is present but incomplete.

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 and front-loaded: the main action and output format appear first, followed by a single optional-behavior sentence. There is no redundant wording 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?

This is a simple zero-required-parameter tool, and the input schema richly documents all parameters including the LLM-specific returnRawBase64 guidance. The description could have stated the returned file path contract explicitly, but the schema's reference to 'saved file path' plus the 'save as PNG' side effect make it sufficient for correct invocation.

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 all four parameters are already documented. The description adds only a simple restatement of elementUUID's optional capture behavior, which provides marginal value beyond the schema but does not introduce any new parameter semantics.

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 ('Take a screenshot') and the output format ('save as PNG'), and it mentions the optional element-scoped capture mode. It does not explicitly differentiate from sibling appium_screen_recording or other capture tools, but the core purpose is unambiguous.

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 gives no guidance on when to prefer this tool over alternatives such as appium_screen_recording, nor does it mention exclusions or prerequisites. The only usage hint is the optional elementUUID behavior, which is more of a parameter detail than a tool-selection guideline.

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