Evaluate JavaScript

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

No annotations exist, so the description must fully convey behavioral traits. It mentions JSON serialization but omits critical details: whether the expression can have side effects, whether it supports async, or any security implications. The description is insufficient for understanding the tool's full behavior.

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, concise sentence that front-loads the core action. It avoids unnecessary words but could benefit from slightly more structure for readability. Still, it is appropriately sized for the tool's simplicity.

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 lack of output schema and annotations, the description leaves many gaps. It does not explain possible errors, return types beyond 'JSON-serialized', or behavior for complex expressions. The tool runs arbitrary code, which demands more completeness for safe usage.

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 50% (sessionId described, script not). The description adds no extra meaning to the script parameter beyond 'JavaScript expression'. It does not specify format, constraints, or how results are returned. Baseline 3 applies, as coverage is not low enough to require heavy compensation.

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 JavaScript in a page and returns JSON-serialized results. The verb 'evaluate' combined with 'JavaScript expression' precisely defines the action, distinguishing it from sibling tools like clicks or 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?

No usage guidelines provided. The description does not indicate when to use this tool over alternatives, nor does it mention prerequisites or exclusions. Sibling tools cover various actions, but there is no comparison or recommendation.

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