evaluate

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

With no annotations, the description itself conveys important behavioral details: promises are awaited, return values are provided with a specific structure on success, and errors are returned on failure or uncaught JS exceptions. It does not mention potential side effects or permission requirements, but the core behavior is well disclosed.

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 concise and well-structured: it opens with the primary purpose, then explains default behavior, promise handling, and return format. Every sentence adds value without unnecessary padding.

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 description covers the key operational aspects: default tab selection, promise resolution, and return/error shapes. Since there is no output schema, this return information is essential and present. Minor omissions like tab-not-found behavior or special return types prevent a perfect score, but overall it is contextually sufficient.

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 0%, so the description must clarify parameters. It explains that expression is a JavaScript expression and that tab_id defaults to the first page tab when omitted. This adds meaningful context beyond the raw schema, though it could be more detailed about expression syntax or edge cases.

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: evaluating a JavaScript expression in a Chrome tab. This specific verb+resource distinction separates it from sibling tools like list_tabs and navigate, which have different purposes.

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 usage context by noting that the first page tab is used when tab_id is omitted, but it does not explicitly compare with alternatives or state when to use this tool over cdp_command or other siblings. The intended use is implied but not formally contrasted.

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