screenshot

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

With no annotations provided, the description carries full burden. It discloses that the tool returns an image for analysis and optionally saves to a file, which are useful behavioral traits. However, it lacks details on permissions needed, potential side effects (e.g., screen interruption), or error handling, leaving gaps for a mutation 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 extremely concise with two sentences that directly state the action, return value, and optional feature. Every word earns its place, and it is front-loaded with the core purpose, making it efficient and easy to parse.

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?

Given the tool's moderate complexity (capturing screenshots with optional saving), no annotations, and no output schema, the description is minimally adequate. It covers the basic operation and return, but lacks details on output format (e.g., image type, size), error cases, or dependencies, leaving room for improvement.

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 the schema already documents both parameters (device_id and save_path) with their descriptions. The description adds no additional meaning beyond what the schema provides, such as clarifying the optional nature or usage context, meeting the baseline for high coverage.

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 specific action ('Take a screenshot') and target resource ('of the Android device'), distinguishing it from all sibling tools which perform different operations like shell commands, app management, or UI interactions. It precisely identifies the tool's unique function in the context.

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 provides no guidance on when to use this tool versus alternatives. It doesn't mention prerequisites (e.g., device connectivity), scenarios where screenshotting is appropriate, or how it differs from other visual tools like get_ui_tree. Usage is implied but not explicitly stated.

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