browser_eval

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

Discloses that execution is observable by page scripts, which is a key behavioral trait. Without annotations, the description should provide more about error handling, return value, or side effects, but it does not.

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, front-loaded with the core purpose. Every sentence provides unique value without redundancy.

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 high schema coverage, single parameter, and no output schema, the description adequately covers purpose and usage guidelines. It could improve by noting that the tool returns the expression's evaluated result, but overall is sufficiently complete for its simplicity.

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% for the single parameter. The tool description adds minimal value beyond the schema, merely restating the same information. Baseline score of 3 applies.

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 it evaluates a JS expression in the page's main execution world. Verb 'evaluate' and specific resource differentiate it from sibling tools that perform other browser actions.

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?

Explicitly advises to use sparingly and prefer AOM + action tools, providing clear when-to-use guidance. However, it lacks explicit exclusions or detailed alternative conditions.

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