browser_execute_js

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

Annotations provide readOnlyHint=false and openWorldHint=true. The description adds the return format (JSON or str fallback) but does not disclose potential side effects (like modifying page state) or error handling. Since annotations already flag mutability, the description adds limited behavioral context beyond the return.

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 sentence with no wasted words. It efficiently conveys the action, context, and return behavior.

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?

For a simple tool with one parameter and an output schema (known to exist), the description covers the basic behavior and return format. It mentions the fallback for non-serializable values, which is helpful. However, it omits potential safety considerations (e.g., timeout, execution context) that could be useful 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% for the single 'script' parameter, with schema description 'JavaScript to run in the page context'. The tool description adds no additional meaning beyond what the schema provides, so 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?

The description clearly states the action ('Execute JavaScript') and the resource ('in the page context'), with a specific output format (JSON, with fallback). It distinguishes this tool from siblings like browser_get_text or browser_click, as it allows arbitrary script execution.

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?

The description implies usage when custom JavaScript needs to be executed and results obtained, but it does not explicitly state when to prefer this over alternatives (e.g., for simple text extraction, use browser_get_text). No guidance on when not to use it or potential risks.

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