firefox_eval

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

With no annotations, the description carries full burden for behavioral disclosure. It only notes that 'obvious cookie/storage extraction is blocked,' which is a constraint, but omits details like return values, synchronicity, or side effects on page state.

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 that conveys the core functionality with no wasted words. It is front-loaded and efficiently states the action.

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 the tool's ability to execute arbitrary JavaScript, the description is insufficient. It lacks explanation of return values, error handling, sandboxing, or integration with other tools, making it hard for an agent to use correctly without additional context.

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 67% (parameters sessionTabId and frameRef have descriptions, but script lacks one). The description adds no information about parameters, such as the type of script expected or the role of frameRef, failing to compensate for the gap.

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 explicitly states 'Run page JavaScript for local browser automation,' clearly indicating the tool's purpose. The verb 'run' and resource 'page JavaScript' are specific, and it is distinct from siblings like firefox_click or firefox_navigate.

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 does not provide guidance on when to use this tool versus alternatives. It only mentions a limitation (cookie/storage extraction blocked) but no explicit conditions or scenarios for preferred usage.

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