playwright__browser_evaluate

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

Annotations already provide destructiveHint=true and readOnlyHint=false, indicating the tool can modify page state. The description adds no further behavioral context (e.g., that it can change the DOM, trigger side effects, or require element permission). It does not contradict annotations, but lacks additional transparency.

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, clear sentence. It is concise and front-loaded with the key action. However, it could be more informative within the same length by including a brief note about return values or when to use the element parameter.

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?

No output schema is provided, and the description does not mention the return value (text or saved file). The agent is left guessing whether the result is returned as text or saved. For a tool that evaluates arbitrary JavaScript, this is a significant gap. The filename parameter description in the schema partially compensates, but the tool description should clarify.

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 all parameters have basic descriptions. The tool description itself adds no extra meaning beyond the schema. The function parameter's schema description is moderately helpful (showing syntax), but the overall description does not elaborate on how parameters interact or constraints.

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 ('Evaluate JavaScript expression') and the target ('on page or element'). It distinguishes this from other browser interaction tools like click or navigate. However, it does not explicitly differentiate from the sibling 'playwright__browser_run_code_unsafe', which could cause confusion.

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., when to use run_code_unsafe instead). The description does not include any context about prerequisites, typical use cases, or exclusions. The agent must infer 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.