chrome_evaluate

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

With no annotations available, the description carries the full burden of behavioral disclosure. It states the tool executes JS and returns a result, but lacks critical details such as potential side effects (e.g., page mutation, network requests), blocking behavior, error handling, or the serialization format of the returned result. The description gives no hint about the risks or limitations of running arbitrary JavaScript.

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, simple sentence: 'Execute JavaScript in the page context and return the result.' It is optimally concise, containing no filler, redundancy, or unnecessary details. Every word contributes to the core function.

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?

The tool has minimal annotations and no output schema, so the description must explain the return format, error behavior, and potential side effects. The current description merely says 'return the result' without specifying what the result looks like (e.g., JSON, raw value) or how errors are surfaced. For a tool capable of running arbitrary code, this is insufficient for an agent to safely and correctly invoke it.

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?

The input schema covers both parameters (expression and tab_index) with descriptions, achieving 100% schema coverage. The description adds marginal value by clarifying that execution happens in the context of the page, but the schema already specifies 'JavaScript expression to evaluate.' No additional syntax or format details are provided beyond the schema.

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 tool's function: 'Execute JavaScript in the page context and return the result.' It identifies a specific verb (execute) and resource (JavaScript in page context), which distinguishes it from sibling tools that handle navigation, clicking, typing, etc. The purpose is unambiguous and cannot be confused with other chrome_* tools.

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 provides no guidance on when to use this tool versus alternatives. It does not mention scenarios where evaluate is preferred (e.g., custom scripting, data extraction) or when other tools like click, type, or navigate should be used instead. There are no prerequisites, edge cases, or exclusionary instructions.

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