Evaluate JavaScript

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

Annotations already declare destructiveHint=true and readOnlyHint=false, so the destructive nature is known. The description adds that the execution is 'bounded' and returns a 'JSON-safe result', which provides minor additional context. However, it does not explain what 'bounded' entails (e.g., sandboxing, time limits) or mention any potential side effects beyond mutation.

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 only two sentences, no redundant words. The first sentence directly states the action and output, followed by a brief behavioral note. Every word serves a 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?

Given the complexity of running arbitrary JavaScript and the existence of an output schema, the description is minimal. It does not cover important context like security implications, performance impact, or the meaning of 'bounded'. For a potentially dangerous tool, more guidance on safe usage 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?

Schema coverage is 100% with each parameter described in the schema. The description does not add new semantic meaning to parameters like script or args beyond what the schema already provides. It only reiterates that the result is JSON-safe, which is implied by the max_chars parameter.

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 runs a JavaScript function body and returns a JSON-safe result, indicating its purpose. However, it does not explicitly distinguish it from sibling tools like page_click or element_click that also interact with the page, though the unique ability to execute arbitrary JavaScript sets it apart.

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?

No guidance is provided on when to use this tool versus alternatives such as page_navigate or element_click. The description lacks context about appropriate scenarios or prerequisites, leaving the agent to infer usage solely from the tool's name and basic function.

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