Playwright MCP Server

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It states the action ('Click') but lacks details on what happens after the click (e.g., page navigation, error handling, or side effects), permissions needed, or any rate limits. This is inadequate for a tool that performs an interactive action in a browser context.

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 that front-loads the core action without unnecessary words. It efficiently communicates the tool's purpose, making it easy for an agent to parse and understand quickly.

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 complexity of interacting with iframes in a browser automation context, the description is insufficient. No annotations exist to cover safety or behavioral traits, and there's no output schema to explain return values. The description fails to address critical aspects like error conditions, what constitutes a successful click, or how it integrates with the broader Playwright toolset.

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 clear descriptions for both parameters ('iframeSelector' and 'selector'). The description adds no additional semantic information beyond what the schema provides, such as examples or constraints on selector syntax. Baseline score of 3 is appropriate since the schema adequately documents the parameters.

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 action ('Click') and target ('an element in an iframe on the page'), making the purpose immediately understandable. It distinguishes from sibling tools like 'playwright_click' by specifying the iframe context, though it doesn't explicitly mention how it differs from other iframe-related tools like 'playwright_iframe_fill'.

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. It doesn't mention prerequisites (e.g., needing an iframe present), when not to use it (e.g., for non-iframe elements), or compare it to similar tools like 'playwright_click' or 'playwright_iframe_fill', leaving the agent to infer usage from context alone.

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