Phone Buzz

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

With no annotations, the description carries the full burden and does add genuine behavioral context: the action only takes effect if the page is open, which is a real caveat. It stops short of saying whether an unmet precondition is a silent no-op or an error, and it doesn't touch on return behavior.

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?

A single compact sentence, front-loaded with the action, followed by the precondition and the parameter example. Nothing is wasted, though the parenthetical placement is slightly awkward.

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 one-parameter tool with an output schema, the description is nearly sufficient: it covers the action, the precondition, and the input format. The unresolved overlap with phone_vibe is the main completeness gap.

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 has 0% description coverage for the lone parameter, so the description must compensate and does: it names the parameter, gives units (ms), and provides a concrete example array. It doesn't explain that the values alternate on/off durations, but the example makes the intent clear.

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?

States a specific verb and resource ('Vibrate the phone') with the pattern input, so the agent knows exactly what happens. It does not differentiate from the near-identical sibling phone_vibe, which leaves ambiguity about which vibration tool to pick.

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 only guidance is a parenthetical precondition ('if the page is open'). There is no statement of when to choose this over phone_vibe, phone_say, or phone_sounds, and no mention of what happens if the condition is unmet.

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