browser_key_down

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

With no annotations, the description discloses the core behavior (key remains down until key_up) but omits details about timeouts, focus loss, or how key-down state interacts with page navigation.

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?

One sentence, immediately states the action and its termination condition, with no 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?

The tool is simple, but the description lacks guidance on key format and does not specify any return value or error behavior. Given the minimal schema and no annotations, a bit more detail would be expected.

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 description does not explain the 'key' parameter format (e.g., 'Enter' vs 'enter'), and the schema's coverage only describes pageId and sessionId. The tool's most important parameter is left ambiguous.

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 uses the specific verb 'Hold' with a clear object 'a keyboard key' and explicitly names the companion tool browser_key_up, distinguishing it from siblings like browser_press_key.

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 implies a paired usage with browser_key_up but does not state when to prefer holding over pressing, nor does it reference alternatives like browser_press_key.

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