browser_evaluate

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

The description adds no behavioral context beyond the annotations. It does not disclose that evaluating JavaScript may have side effects, alter page state, or require permissions, even though annotations already flag destructiveness. The description is silent on what actually happens when the tool runs.

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, front-loaded sentence with no wasted words. It is concise and easy to parse, though it may be slightly too terse for a tool of this complexity, but it earns its place as a clear summary.

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 tool's complexity (arbitrary JavaScript execution, destructive potential, no output schema), the description is incomplete. It lacks information about when to choose this tool over browser_run_code_unsafe, safety considerations, return behavior, or side effects. The description alone is not sufficient for an agent to use it correctly in varied contexts.

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%, so the schema already documents all four parameters. The description's phrase 'on page or element' provides a minimal hint that aligns with the target/element parameters but adds no meaningful semantics beyond the schema, so baseline 3 is appropriate.

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 uses a specific verb 'Evaluate' with the resource 'JavaScript expression on page or element', clearly conveying the tool's purpose. It is distinct from most sibling tools, though it does not explicitly differentiate itself from browser_run_code_unsafe, preventing a top score.

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 given on when to use this tool versus alternatives such as browser_run_code_unsafe. There is no mention of prerequisites, exclusions, or typical use cases, leaving the agent to infer usage solely from the purpose.

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