Playwright MCP

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

Annotations indicate readOnlyHint=false, openWorldHint=true, and destructiveHint=true, covering safety and scope. The description adds value by specifying that the code runs Playwright snippets, implying browser automation with potential side effects, which aligns with annotations. However, it doesn't detail execution limits, error handling, or resource implications beyond the annotations.

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 phrase 'Run Playwright code snippet' that is front-loaded and wastes no words. It directly conveys the core purpose without unnecessary elaboration, making it highly concise and well-structured.

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), annotations provide safety hints, and the schema fully describes the parameter. However, with no output schema and minimal description, it lacks details on return values, error cases, or execution context, leaving gaps for an agent to handle this powerful tool effectively.

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 the schema fully documenting the 'code' parameter as a JavaScript function for Playwright execution. The description adds no additional parameter semantics beyond what the schema provides, so it meets the baseline for high coverage without extra value.

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 'Run Playwright code snippet' clearly states the action (run) and resource (Playwright code snippet), distinguishing it from siblings like browser_click or browser_navigate that perform specific actions. However, it doesn't explicitly differentiate from browser_evaluate, which might also execute code, making it slightly less specific.

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 like browser_evaluate or other specific interaction tools. The description lacks context about use cases, prerequisites, or exclusions, leaving the agent to infer usage based on tool names alone.

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