execute_js

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It reveals key behavioral traits: CDP vs IPC, return value vs no return value, no focus change, and fire-and-forget nature. It does not cover error handling or potential side effects, but the disclosed information is substantial and accurate.

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 exceptionally concise and well-structured. It leads with the core purpose in one sentence, then provides a clear conditional explanation in the second. Every word contributes value, with no redundancy or filler.

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 moderate complexity and absence of an output schema, the description adequately explains return value behavior in both modes and the focus side effect. It omits details like error handling or page type restrictions, but these are not essential for an agent to invoke the tool correctly.

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 already covers all three parameters with descriptions (100% coverage), setting a baseline of 3. The tool description adds meaning by explaining how the presence or absence of 'tab' alters execution mode and return value, and indirectly clarifies that 'quiet' is only relevant in IPC mode. This goes beyond the schema's individual parameter descriptions.

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 purpose with a specific verb and resource: 'Execute JavaScript in a page.' It distinguishes itself from all sibling tools, none of which execute JavaScript. The two execution modes (with/without 'tab') are also clearly explained, adding functional clarity.

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 clear guidance on when to use each mode: with 'tab' for CDP execution returning a result, without 'tab' for IPC fire-and-forget with no return value. However, it does not explicitly mention alternative tools or exclusion criteria, so it stops short of full when/when-not guidance.

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