evaluate_script

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

The description discloses that the response is returned as JSON and that values must be JSON-serializable. This adds value beyond the schema. However, it does not mention side effects, execution context (e.g., page sandboxing), or behavior for non-serializable returns. Since no annotations are provided, the description carries the full burden, and it covers key behavioral aspects adequately.

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, front-loaded sentence that concisely conveys the core purpose and a key constraint (JSON-serializable return). Every word earns its place, and there is no redundant information.

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 complexity of executing arbitrary JavaScript, the description is somewhat incomplete. It lacks details on execution context (e.g., page scope, async support), error handling for non-serializable returns, and potential side effects. The absence of an output schema increases the need for such information. The description covers the basics but leaves gaps.

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%, so baseline is 3. The description does not add significant meaning beyond the schema; it reiterates the JSON constraint but does not elaborate on the 'args' parameter or provide examples beyond what the schema already offers.

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 evaluates a JavaScript function inside the currently selected page. It uses a specific verb ('evaluate') and resource ('JavaScript function'), and the context ('inside the currently selected page') distinguishes it from sibling tools like click or type_text, which do not execute arbitrary JavaScript.

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 does not provide explicit guidance on when to use this tool versus alternatives. While it is the only tool that executes JavaScript, no when-not-to-use or alternative recommendations are given. The usage context is implied but not explicitly stated.

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