Evaluate JavaScript

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

The annotations already provide readOnlyHint and destructiveHint, and the description does not contradict them. However, the description does not disclose that executing arbitrary JavaScript could have side effects beyond the provided hints, so it adds little transparency on top of 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 concise, using two sentences to convey the core functionality and parameter behavior without unnecessary details or repetition. It is well-structured 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?

The description is adequate for the simple purpose but omits an explanation of the 'filename' parameter and does not state what the tool returns. While no output schema exists, mentioning the return behavior or the purpose of saving to a file would improve 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?

The schema covers all parameters with descriptions, and the tool description clarifies the 'function' and 'target' parameters but omits any explanation of 'filename'. Since schema coverage is complete, the description adds only marginal value beyond the existing parameter descriptions.

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 tool's purpose as running JavaScript in the page, which is a distinct action from navigation, clicking, or other browser operations. It provides a specific verb and resource, making it easily distinguishable from sibling tools.

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 includes a concrete example of how to pass the function as a string and explains the behavior of the optional target parameter. While it does not explicitly state when to prefer this tool over alternatives, the example and parameter explanation provide practical guidance.

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