screenshot

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

No annotations are provided, so the description carries full burden. It mentions the output format (PNG) but doesn't disclose behavioral traits like whether it's a read-only operation, performance implications, whether it blocks, or error conditions beyond aspect ratio mismatch. A screenshot tool could have significant side effects (e.g., freezing the app), which aren't mentioned.

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?

Two sentences, front-loaded with purpose, then parameter behavior. Every sentence is informative and no waste.

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?

For a no-annotation, no-output-schema tool with 2 parameters, the description covers the essentials but leaves gaps: no mention of read-only nature, error handling beyond aspect ratio, or performance. It's adequate but not rich.

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 coverage is 100%, so the schema already documents width and height semantics. The description adds marginal value by explaining aspect-ratio behavior and error conditions, but the schema already covers this. Baseline for high coverage is 3, but the explicit error condition adds a bit.

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 the current frame as a PNG. It's clear what the tool does, though it doesn't differentiate from sibling tools like list_screens (which likely just lists screens without capturing). The scope (current frame) is precise.

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 usage for scaling, but doesn't say when to use this versus alternatives like get_screen_state or list_screens. No explicit when/when-not guidance is provided, only conditional behavior for parameters.

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