Playwright MCP

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

Annotations already provide readOnlyHint=true, destructiveHint=false, and openWorldHint=true. The description adds behavioral context about what 'previous page' means (navigation history) that isn't captured in annotations. It doesn't mention potential failures (e.g., no history) or side effects, but with good annotation coverage, this is acceptable.

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 wasted words. It's front-loaded with the core action and appropriately sized for a simple navigation tool with no parameters.

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 simplicity (0 parameters, no output schema) and comprehensive annotations, the description is mostly complete. It could benefit from mentioning potential edge cases (e.g., what happens with no history), but for a basic navigation operation with good structured data, it provides sufficient context.

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?

The tool has 0 parameters with 100% schema description coverage. The description doesn't need to explain parameters, and the baseline for 0 parameters is 4. The description appropriately focuses on the action rather than 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 'Go back to the previous page' clearly states the specific action (go back) and resource (previous page) with a precise verb. It distinguishes from sibling tools like 'browser_navigate_forward' by specifying directionality, and from 'browser_navigate' by focusing on navigation history rather than new URLs.

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 implies usage context (when there is a previous page in browser history) but doesn't explicitly state when not to use it or name alternatives. It doesn't provide prerequisites like requiring an open browser session, though this might be inferred from the tool family context.

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