cdp_evaluate

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

With no annotations, the description carries full responsibility for behavioral disclosure. It discloses the core action (evaluating JS) and the return behavior, but omits side effects, error handling for non-serializable results, async behavior, and security implications of executing arbitrary code in the page.

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, front-loaded sentence with no wasted words. It efficiently conveys the essential purpose and return behavior.

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 under-specified. It lacks information about side effects, return value limitations, error conditions, and usage context. No output schema or annotations exist to compensate, making the description inadequate for safe and correct invocation.

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 coverage is 50%; the expression parameter lacks a schema description. The tool description clarifies that 'expression' is JavaScript code, but does not add detail about evaluation context, async handling, or result serialization. The session_id parameter is adequately described in the schema.

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 runs a JavaScript expression in the page and returns the JSON-serializable result. This specific verb+resource combination distinguishes it from sibling tools like cdp_click or cdp_type, which perform DOM interactions rather than arbitrary JS evaluation.

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, no exclusions, and no mention of prerequisites beyond the parameters. The usage context is only implied by the tool's purpose, not explicitly stated.

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