screenshot

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It does disclose a key behavior: the tool returns an inline JPEG with coordinate mapping, and that coordinates are absolute. It also discloses the alternative behavior of saving a PNG to disk. However, it doesn't disclose other important behaviors such as what happens with the region/window/monitor parameters, whether the screenshot captures the entire screen by default, or any side effects. The description adds some value but leaves gaps.

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 two sentences with zero waste. The primary behavior is front-loaded in the first sentence, and the alternative usage is in the second. Every word earns its place.

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 has 7 parameters, no output schema, and no annotations, the description is incomplete. It explains the core output (inline JPEG + coordinate mapping) and the path alternative, but it doesn't explain the other 6 parameters, the default capture scope, or how coordinates are returned. An agent would likely need to guess or experiment to use the tool correctly for non-default scenarios.

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 0%, so the description must compensate for the 7 undocumented parameters. The description only mentions 'path' (save full-res PNG to disk) and implicitly references the inline JPEG output. It does not explain the meaning of region, window, monitor, quality, max_width, or include_cursor. This is a significant gap for a tool with 7 parameters and no schema descriptions.

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 states a specific verb and resource: 'Screenshot to inline JPEG + coordinate mapping (coords are absolute).' It clearly identifies the tool's primary function and distinguishes it from sibling tools like list_monitors or find_text_on_screen. However, it doesn't explicitly name a sibling alternative for comparison, so it falls short of a 5.

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 clear context for when to use the tool and even gives an alternative usage: 'Pass path to save full-res PNG to disk instead (no token cost) — for debugging OCR without an inline image.' This explains a specific scenario (debugging OCR) and the trade-off (token cost). It doesn't explicitly state when NOT to use the tool or name alternative tools, but the guidance is strong enough for a 4.

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