Evaluate JavaScript

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

No annotations are provided, so the description carries full burden. It only mentions 'evaluate' without disclosing side effects (e.g., DOM mutation, global state changes), error handling, return value format, or that execution is synchronous in the page context. The phrase 'browser-side' hints at the execution context but is insufficient for a tool that runs arbitrary code.

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, but it is also under-specified. It is not verbose, but it could be more informative without increasing length significantly. The front-loading is present (verb first), but the brevity sacrifices helpfulness.

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 7 parameters, no output schema, and no annotations, the description is too minimal. It does not explain what the tool returns (evaluated result), how promises are handled, error scenarios, or execution context details. The schema covers parameter descriptions, but the overall behavioral context is lacking for a tool executing arbitrary code.

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% (all 7 parameters have descriptions in the input schema). The tool description itself adds no additional parameter meaning beyond the schema; it merely restates the general purpose. Baseline 3 is appropriate since the schema carries the parameter documentation.

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 verb 'Evaluate' and the resource 'JavaScript in the page', and specifies 'browser-side expression or statements'. This uniquely identifies the tool among siblings like dev_browser_click, dev_browser_fill, etc., which do not execute arbitrary 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 the tool is for executing JavaScript in the page, but it does not explicitly state when to use it versus alternatives (e.g., dev_browser_click for specific actions). No when-not-to-use or exclusion criteria are mentioned; the guidance is merely implied by the verb.

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