Playwright MCP Server

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

Annotations already indicate this is a destructive, non-read-only operation with open-world hints. The description adds minimal context by specifying it uploads files, but doesn't elaborate on behavioral traits like what happens on cancellation (implied by schema), error handling, or UI interactions. 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 a single, efficient sentence with zero waste. It's front-loaded with the core action ('Upload') and clearly states the scope ('one or multiple files'), making it easy to parse 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 tool's complexity (destructive file operations), lack of output schema, and rich annotations, the description is incomplete. It doesn't explain what 'upload' means in this browser context (e.g., to a web form), potential side effects, or result expectations, leaving significant gaps for agent understanding.

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%, fully documenting the 'paths' parameter. The description adds no additional meaning beyond what the schema provides, such as file type restrictions or upload destination. With high schema coverage, the baseline score of 3 is appropriate.

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 ('upload') and resource ('files'), specifying it can handle 'one or multiple files'. However, it doesn't differentiate from sibling tools like browser_drag or browser_select_option, which might also handle file interactions in different contexts.

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. It doesn't mention prerequisites (e.g., needing an active browser session), exclusions, or how it differs from other file-related operations in the sibling list, 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.