Run JavaScript in the page

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

With no annotations, the description carries full responsibility for behavioral disclosure. It mentions returning the result and the dashboard page context, but does not explain potential side effects (e.g., arbitrary code execution, navigation, or state mutation) or any safety/permission considerations. This is adequate but not rich.

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 two concise sentences. The first sentence front-loads the core action, and the second adds valuable use-case context without any unnecessary words.

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 a simple signature (one parameter, no output schema). The description sufficiently covers purpose, use cases, and return behavior. It could optionally mention the result type or the fact that it operates on the currently open dashboard page, but overall it is complete for the tool's complexity.

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 schema already provides a clear description for the single parameter 'js' ('JavaScript expression or IIFE to evaluate in the page context'). The tool description adds minimal extra parameter meaning beyond that, so it meets the baseline of 3.

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: 'Run a small JavaScript expression in the dashboard page and return its result.' It uses a specific verb ('run') and resource ('JavaScript expression in the dashboard page'), and distinguishes itself from sibling tools by highlighting unique use cases like 'reading React state' and 'clicking via JS'.

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 when to use it ('Useful for reading React state, clicking via JS, or advanced automation') and gives context. However, it does not explicitly state when NOT to use it or directly compare with alternatives like browser_click or browser_text, so it falls short of a 5.

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