mcp-vnc

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

With no annotations provided, the description carries full burden for behavioral disclosure. It states the action but omits critical details: whether this requires specific permissions, if it captures the entire screen or a region, the output format (e.g., image type), error conditions, or side effects. The description adds minimal value beyond the basic action.

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 a single, direct sentence with zero wasted words. It is appropriately sized for a simple tool and front-loads the core purpose immediately. Every word earns its place by conveying essential information without redundancy or fluff.

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 (screen capture with timing control) and lack of annotations or output schema, the description is incomplete. It fails to address key aspects like return values (e.g., image data or file path), error handling, or dependencies on VNC state. The description does not compensate for the absence of structured metadata.

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 input schema has 100% description coverage, with the 'delay' parameter fully documented in the schema itself. The description adds no additional parameter semantics beyond what the schema provides, such as typical use cases for delays or interaction with other tools. This meets the baseline score of 3 given high schema 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 current screen'), using a precise verb-noun combination. It effectively distinguishes this tool from its siblings (e.g., vnc_click, vnc_key_press) by focusing on screen capture rather than input simulation or navigation.

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. While the tool's purpose is clear, it lacks context about prerequisites (e.g., VNC connection status), timing considerations, or comparisons to other screenshot methods. No explicit when/when-not statements or sibling tool references are included.

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