Circuitry MCP Server

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

With no annotations provided, the description carries full burden and does well by disclosing key behavioral traits: it captures visual content as a PNG, returns base64-encoded data, and specifies that Claude can analyze the output visually. However, it doesn't mention potential limitations like screen size constraints, performance implications, or authentication requirements.

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 efficiently structured with a clear purpose statement followed by bulleted usage examples and output format details. Every sentence earns its place, and the information is front-loaded with the core functionality stated first.

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 single-parameter tool with no annotations and no output schema, the description provides good coverage of purpose, usage context, and output format. However, it could be more complete by mentioning potential error conditions or limitations, such as what happens if the specified screen doesn't exist or if capture fails.

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 schema has 100% description coverage for its single parameter, but the description adds valuable context about the parameter's behavior: 'uses selected screen if not specified.' This clarifies the default behavior when screenId is omitted, which isn't captured in the schema description alone.

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 tool's purpose with specific verb ('capture') and resource ('Designer screen'), specifying the output format ('PNG image'). It distinguishes from siblings like screen.get, screen.list, or screen.update by focusing on visual capture rather than metadata retrieval or modification.

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 explicitly provides usage context: 'Use this to verify layouts and catch visual issues like: - Clipped content - Poor contrast - Overlapping elements - Sizing problems.' This gives clear guidance on when to use this tool versus other screen-related tools that handle creation, deletion, or metadata operations.

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