browser_eval

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

With no annotations, the description must disclose behavioral traits, but it only states 'execute JavaScript'. It fails to mention whether the execution is synchronous, what happens to return values, security implications, or potential side effects (e.g., DOM modifications). This is insufficient for safe and effective use.

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 extremely concise (one sentence), but conciseness comes at the cost of informativeness. It is front-loaded and efficient, yet it sacrifices necessary detail, earning a middle score.

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 potential for arbitrary execution (no output schema, no annotations), the description is incomplete. It omits return behavior, error handling, and scope of execution. The single parameter is documented only minimally, leaving critical gaps for an AI agent.

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 100%, and the description adds no extra meaning beyond the schema's 'JavaScript expression' description. The value conveyed is identical, so it meets the baseline of 3 for high coverage without adding new insight.

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 identifies the action (execute JavaScript) and the context (page context), distinguishing it from sibling tools like browser_click or browser_goto which perform specific UI actions. However, it lacks specificity about the execution environment or return value, making it slightly less than exemplary.

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 (e.g., browser_watch or other interaction tools). There are no prerequisites, exclusions, or context hints, leaving the agent to infer appropriate usage from the name alone.

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