designer-mcp

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

With no annotations provided, the description carries the full burden and effectively discloses key behaviors: it returns a filesystem path to a PNG in /tmp, specifies the output format ({ path, bytes }), and mentions a follow-up action (Read tool). However, it lacks details on potential errors or limitations.

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 front-loaded with the core purpose, followed by essential details on output and usage, with every sentence earning its place and no wasted words.

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 (screenshot functionality with one optional parameter) and no output schema, the description is mostly complete, covering purpose, output, and a follow-up action, though it could include more on error handling or constraints.

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 description coverage is 100%, so the baseline is 3. The description adds minimal value beyond the schema by implying the selector is optional and used for targeting elements, but does not provide additional syntax or format details.

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 verb ('Screenshot') and resource ('the current page or a specific element selector'), distinguishing it from sibling tools like designer_close, designer_open, and designer_pick by specifying its unique screenshot functionality.

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?

It provides clear context for usage by specifying 'the current page or a specific element selector' and mentions an alternative action ('Read with the Read tool'), but does not explicitly state when not to use it or compare directly to sibling tools.

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