designer-mcp

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

No annotations are provided, so the description carries the full burden. It discloses key behavioral traits: it opens a URL, launches Chromium if not running, and is intended as a preparatory step. However, it lacks details on error handling, timeouts, or what happens if the URL is invalid, which are important for a tool that interacts with a browser.

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 extremely concise and front-loaded, with two sentences that efficiently convey the action, conditional behavior, and usage context. Every sentence earns its place by providing 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 low complexity (1 parameter, no output schema, no annotations), the description is mostly complete. It covers purpose, usage, and key behavior. However, it could improve by mentioning potential side effects (e.g., browser window focus) or error scenarios, slightly reducing completeness for a tool that launches external processes.

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 100%, with the schema fully documenting the 'url' parameter. The description does not add any meaning beyond the schema (e.g., URL format examples or constraints), so it meets the baseline of 3 where the schema does the heavy lifting without extra value from the description.

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 ('Open a URL') and the target resource ('in the designer's headed Chromium'), including the conditional behavior ('launches it if not running'). It distinguishes from siblings by mentioning designer_pick as a subsequent step, showing awareness of the tool's role in the workflow.

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 explicitly provides when-to-use guidance by stating 'Use this before designer_pick,' establishing a clear sequence in the workflow. This directly addresses when to use this tool versus alternatives (like designer_screenshot or designer_close) by positioning it as a prerequisite step.

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