browser_evaluate

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

Without annotations, the description carries the full burden. It discloses that JavaScript is executed in the page context and returns JSON, and provides examples. It does not warn about security risks or limitations (e.g., cross-origin restrictions), but the core behavior is adequately described.

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 very concise: two sentences plus examples. It front-loads the purpose, then explains the parameter format, and ends with output type. Every sentence earns its place without redundancy.

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 single parameter and output schema existence, the description is mostly complete. It explains input (script type) and output (JSON). It lacks mention of error handling (e.g., script syntax errors or exceptions), but the output schema likely covers return types.

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 only defines 'script' as a string with no description. The description adds significant value by explaining it must be a JS expression or function body returning a value, and provides clear examples. This fully compensates for the 0% schema description coverage.

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 'Execute JavaScript', the resource 'current page context', and the outcome 'return the result'. It distinguishes itself from sibling tools (e.g., click, navigate) by focusing on arbitrary script execution.

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 explicitly state when to use this tool versus alternatives. While the nature of JavaScript execution implies custom logic, no guidance is given on when not to use it (e.g., for simple selection which other tools handle). Implicit understanding is reasonable but not stated.

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