zen_evaluate

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

The description only states the basic operation without disclosing behavioral traits like potential side effects, error handling, or security implications. Since annotations are absent, more detail is needed for a tool that executes arbitrary JavaScript.

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, front-loaded sentence with no extraneous words. It efficiently conveys the core function.

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?

While simple, the description omits details about the return value format, error handling, or whether the script is executed in a sandbox. For a tool that runs arbitrary code, slightly more context would be beneficial.

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 input schema already fully describes the script parameter (coverage 100%). The description adds no additional meaning beyond confirming execution context, so it meets the baseline average.

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 verb 'Execute', the resource 'JavaScript in the page', and the outcome 'return the result'. It distinguishes well from sibling tools like zen_click or zen_screenshot.

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 when to choose it over other page interaction tools. The description lacks context about appropriate use cases.

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