browser_evaluate

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

With no annotations provided, the description carries the full burden. It mentions the permission requirement but does not disclose return values, side effects on the page, or whether evaluation can modify state. This is minimal behavioral disclosure for an evaluation tool.

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 concise sentence that is easy to parse and front-loaded with the action. It wastes no words, but the brevity comes at the cost of essential information, so it is not a 5.

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?

For a tool that executes arbitrary JavaScript, the description is incomplete. It lacks any context about expected behavior, return format, or relationship to sibling tools. No output schema or annotations exist to compensate, so the description should have provided more.

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%, with pageId and sessionId already documented in the schema. The description adds no meaning for the 'expression' parameter, which has no schema description, leaving the most important parameter semantically unexplained.

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 core action 'Evaluate JavaScript', which is a specific verb+resource combination. However, it does not differentiate from the sibling tool 'browser_run_code', which likely serves a similar purpose, so it falls short of a 5.

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 only mentions a prerequisite (permission enabled) but does not explain context, exclusions, or how it differs from other JavaScript-related tools like 'browser_run_code'.

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