capture_screen_base64

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

No annotations are provided, so the description carries the full burden. It does disclose the return payload keys (format, bytes, base64), which is useful, but says nothing about device selection, permission/auth requirements, or what happens when no device is connected.

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?

A single front-loaded sentence that states the action and the return shape with no filler. Nothing is wasted.

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 and an output schema exists, so return values needn't be re-explained. However, with zero annotations and an entirely undocumented 'serial' parameter, the description leaves device targeting and prerequisites unstated.

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?

There is one parameter, 'serial', with 0% schema description coverage, and the description does not mention it at all. It neither explains that it selects the target device nor what the default (null) resolves to, so it does not compensate for the schema gap.

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?

States a specific verb and resource ('Capture a screenshot') and specifies the return payload shape ({format, bytes, base64}). The trailing clause implicitly distinguishes it from the inline-image variant (capture_screen), but does not name that sibling explicitly.

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?

Gives a clear selection condition: use when 'a raw base64 payload is preferred over an inline image.' This is a usable when-to-use rule, though it never names the alternative tool (capture_screen) or the file variant (capture_screen_to_file), leaving the routing partly inferential.

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