Playwright MCP

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

Annotations indicate this is a destructive, non-read-only operation with open-world hints, which the description aligns with by implying mutation ('fill'). The description adds value by specifying 'multiple form fields,' suggesting batch capability, though it lacks details on error handling, side effects, or dependencies. No contradiction with annotations exists.

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 a single phrase, 'Fill multiple form fields,' which is front-loaded and wastes no words. It efficiently conveys the core action, though this brevity contributes to gaps in other dimensions.

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 a destructive tool with no output schema and rich annotations, the description is incomplete. It doesn't explain return values, error conditions, or how it integrates with sibling tools (e.g., browser_snapshot for 'ref' values). For a tool that modifies browser state, more context is needed to guide safe and effective use.

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 the schema fully documents the 'fields' parameter and its nested properties. The description adds no additional meaning beyond implying batch processing ('multiple'), which is already clear from the array type in the schema. Baseline 3 is appropriate as the schema handles parameter 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 'Fill multiple form fields' states the action (fill) and resource (form fields), but is vague about scope and differentiation. It doesn't specify whether this is for web forms, desktop applications, or other contexts, nor how it differs from sibling tools like browser_type or browser_select_option that also interact with form elements.

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?

No guidance is provided on when to use this tool versus alternatives. The description doesn't mention prerequisites (e.g., needing a browser session or page snapshot), nor does it compare to similar tools like browser_type (for text input) or browser_select_option (for dropdowns), leaving the agent to guess based on context.

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