Playwright MCP Server

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

Annotations already provide readOnlyHint=true and destructiveHint=false, establishing this as a safe read operation. The description adds valuable context about the limitation that screenshots cannot be used for actions, which goes beyond the annotations. However, it doesn't mention rate limits, file size considerations, or performance implications.

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 consists of just two sentences that are perfectly front-loaded and waste-free. The first sentence states the core purpose, and the second provides critical usage guidance. Every word serves a clear purpose.

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?

For a read-only tool with comprehensive schema documentation (100% coverage) and clear annotations, the description provides adequate context. The main gap is the lack of output schema, but the description compensates somewhat by clarifying the tool's limitations. It could benefit from mentioning the return format or file location details.

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?

With 100% schema description coverage, all parameters are well-documented in the schema itself. The description doesn't add any parameter-specific information beyond what's already in the schema descriptions, so it meets the baseline expectation without adding 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 clearly states the specific action ('take a screenshot') and target resource ('current page'), distinguishing it from sibling tools like browser_snapshot. It provides a precise verb+resource combination that leaves no ambiguity about the tool's function.

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 explicitly provides when-not-to-use guidance by stating 'You can't perform actions based on the screenshot, use browser_snapshot for actions.' This gives clear alternative usage context and distinguishes between screenshot capture and interactive snapshot capabilities.

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