Read Screen

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

Since no annotations are provided, the description carries the burden of behavioral disclosure. It does disclose the most relevant behavior: text-only output rather than an image, plus the structure of the output. However, it does not mention permission needs, failure modes, or limitations such as whether it reflects live UI state.

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 no filler. The core behavioral distinction ('text-only view... no image') is front-loaded, and the output composition is given immediately after.

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?

The tool is simple, has only one optional parameter, and has an output schema, so the description does not need to explain return values in detail. It conveys the essential content and non-image nature, but it is incomplete because it provides no usage guidance and no parameter semantics.

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?

The schema has one undocumented optional 'device' parameter and 0% description coverage, and the tool description never mentions it. The parameter name is self-explanatory, but valid values, default-null behavior, and device selection semantics are left completely unspecified.

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 identifies a specific resource (screen) and a specific delivery mode (text-only, no image) with concrete content (foreground app plus numbered elements). It clearly separates read_screen from screenshot-style siblings, though it does not explicitly name or contrast perceive_screen or get_ui_tree.

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?

No explicit guidance is given for when to use this tool versus alternatives such as get_screenshot or get_ui_tree. The 'no image' phrase implies a text-oriented use case, but the description never states conditions, exclusions, or named alternatives.

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