获取移动端截图

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

The annotations already cover read-only, idempotent, and non-destructive behavior. The description adds useful context beyond those annotations by promising a token-saving compressed image, which helps an agent reason about cost and output size. It does not fully describe how the image is returned, but the safety profile is already established.

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, front-loaded sentence that states the action, the object, and the key benefit. It contains no filler and does not redundantly repeat schema details.

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?

With no output schema and no parameter descriptions, the description leaves important gaps: how the compressed image is returned, where targetId comes from, and how to choose meaningful values for format, quality, and maxWidth. The annotations are strong, but they do not fill these invocation-semantics gaps.

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 0%, and the description does not compensate by explaining any parameter semantics. It does not clarify that targetId identifies the target device, nor how format, quality, and maxWidth interact with the token-saving goal.

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 a real-device screen) and the distinctive output (a compressed image that saves tokens). This differentiates it from sibling tools like mobile_get_logs, mobile_interact, and mobile_read_evidence, which cover different resources or actions.

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 intended use is implied: use this when a mobile screenshot is needed. However, it gives no explicit guidance about when not to use it or which sibling tools to prefer for related tasks such as reading evidence or retrieving logs.

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