eval_js

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

Explains the profile vs clean browser distinction, which is helpful. However, with no annotations, the description should also disclose whether the evaluation is sandboxed, what return types are supported, and potential side effects. Lacks depth on behavioral traits.

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?

Two concise sentences: the first states the core purpose, the second adds parameter guidance. No wasted words, front-loaded with essential 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?

Covers basic functionality and parameter usage. However, with no output schema, it lacks information about return value structure (e.g., object with value/error) and limitations (timeout, error handling). Adequate but not fully complete.

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?

With 0% schema coverage, the description compensates well. It explains the 'useProfile' parameter in detail (purpose, values) and implies 'code' is the JavaScript to run. Both parameters are semantically clear from the description.

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?

Clearly states the action ('Run JavaScript') and scope ('in the active tab and return the result'). Purpose is unambiguous and distinct from sibling tools like ff_eval.

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?

Provides guidance on using the useProfile parameter (with profile vs clean browser), but does not discuss when to choose this tool over alternatives like ff_eval or other browser interaction tools. Usage context is implied but not explicit.

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