MCP-Midscene

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

No annotations are provided, so the description carries the full burden. It discloses the behavioral trait of opening in the current tab, which is useful beyond the basic action. However, it lacks details on error handling, timeouts, or what happens if the URL is invalid, leaving gaps in behavioral context for a navigation tool.

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 two sentences that are front-loaded and waste no words. Every sentence earns its place by stating the core action and a key behavioral constraint, making it efficient and easy to parse.

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 moderate complexity (navigation with one parameter) and no annotations or output schema, the description is minimally adequate. It covers the basic action and a behavioral trait but lacks details on return values, error cases, or integration with sibling tools, leaving room for improvement in completeness.

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 parameter 'url' fully documented in the schema as 'URL to navigate to.' The description adds no additional meaning or context beyond this, such as URL format requirements or examples, so it meets the baseline for high schema coverage without compensating 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 ('navigates') and target resource ('browser to the specified URL'), distinguishing it from sibling tools that perform other browser interactions like clicking, scrolling, or taking screenshots. It explicitly defines the tool's scope as URL navigation.

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 provides clear context by specifying 'Always opens in the current tab,' which helps differentiate it from tools that might open new tabs or windows. However, it does not explicitly state when to use this versus alternatives like other navigation methods or sibling tools, nor does it mention any prerequisites or exclusions.

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