android_screenshot

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

The description discloses an important behavioral caveat: protected windows may deny capture. This aligns with the readOnlyHint and idempotentHint annotations and adds useful transparency about potential failures.

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 extremely concise, using a single sentence that communicates both the core action and an important limitation without unnecessary detail.

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 description is adequate for a parameterless screenshot tool, including a relevant caveat. However, since no output schema is provided, it leaves the exact return format unspecified, though 'as an image' gives a general expectation.

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 tool has no parameters, so no parameter descriptions are needed. The schema already covers this completely.

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's purpose with a specific verb and resource: 'Capture current display as an image'. It is easily distinguished from sibling tools like android_ui_tree or android_shell.

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 implies the tool is for capturing the display, but it does not explicitly state when to prefer it over alternatives or when not to use it. The purpose is clear enough for basic selection, but no direct usage guidance is provided.

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