Playwright MCP

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

Annotations indicate destructiveHint=true and readOnlyHint=false, which the description doesn't contradict. However, the description adds no behavioral context beyond the annotations—it doesn't explain what 'destructive' means here (e.g., changes UI state), rate limits, or error handling. With annotations covering safety, a 3 reflects minimal added value.

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, efficient sentence with zero waste—it directly states the tool's purpose without redundancy. It's appropriately sized for a simple action tool and front-loaded with essential information.

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 (moderate, with destructive behavior), rich annotations, and no output schema, the description is minimally adequate. It covers the basic action but lacks details on outcomes, error cases, or integration with siblings like browser_snapshot for obtaining 'ref'. With annotations, it meets a baseline but could be more informative.

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%, so parameters are fully documented in the schema. The description adds no additional meaning beyond implying dropdown interaction, which is already clear from the tool name. Baseline 3 is appropriate as the schema does the heavy lifting.

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 'Select an option in a dropdown' clearly states the action (select) and target (dropdown), distinguishing it from siblings like browser_click or browser_type. However, it doesn't explicitly differentiate from browser_handle_dialog which might also involve dropdowns, making it slightly less specific than a perfect 5.

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., requiring a page snapshot), exclusions, or comparisons to siblings like browser_click for non-dropdown interactions, 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.