Playwright MCP

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

Annotations indicate destructiveHint=true and openWorldHint=true, which the description doesn't contradict. It adds valuable context by specifying that the code is a JavaScript function invoked with a 'page' argument, clarifying execution behavior beyond the annotations. However, it doesn't mention potential risks like infinite loops or resource consumption.

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 with just three words, front-loading the essential action. Every word earns its place by specifying the tool's core function without redundancy or fluff, making it efficient for quick comprehension.

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 complexity (executing arbitrary code with destructive potential) and lack of output schema, the description is minimally adequate. It identifies the tool's purpose but lacks details on return values, error handling, or safety considerations, leaving gaps for the agent to infer.

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, providing a clear example of the 'code' parameter. The description adds minimal semantics beyond this, only restating 'Playwright code snippet' without elaborating on constraints or best practices. Baseline 3 is appropriate given the schema's thorough documentation.

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 ('Run') and resource ('Playwright code snippet'), making the purpose immediately understandable. It distinguishes from siblings by focusing on executing arbitrary code rather than specific actions like 'browser_click' or 'browser_navigate', though it doesn't explicitly contrast with them.

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. With many sibling tools for specific browser interactions (e.g., browser_click, browser_type), it fails to indicate scenarios where running custom Playwright code is preferable over using dedicated tools, leaving the agent without usage context.

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