Watch Device Events

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

With no annotations, the description carries the full behavioral burden and does well: it specifies the default and maximum timeout, the default max_events, and the early-return condition. It also lists the exact event types and available filters, giving the agent a clear picture of runtime behavior, though it omits any mention of permissions or resource consumption.

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 two tightly packed sentences with no filler, front-loading the core collection behavior and constraints before listing filters. Every phrase adds useful information.

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?

An output schema exists, so return values need not be described, and the core streaming behavior is covered. However, with no annotations and 0% schema description coverage, the omission of device, duration, and interval leaves the definition incomplete for a six-parameter tool.

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 0%, so the description must compensate, but it only explains three of six parameters (timeout_seconds, max_events, kinds). It leaves device, duration, and interval completely unexplained, missing key semantics for half the parameters.

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 a specific verb ('Collect') and resource ('device events') and enumerates the event categories (foreground app, keyboard, screen content, notifications). It is clear what the tool does, but it does not explicitly differentiate from sibling tools that also deal with events or notifications.

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 usage by detailing the streaming behavior and filterable kinds, but it never states when to choose this tool over alternatives like read_notifications or wait_for_screen_change. There are no explicit when-to-use or when-not-to-use conditions.

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