Vibrate the device

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

Annotations already declare readOnly=false, idempotent=false, destructive=false, openWorld=true, so the safety profile is covered. The description adds one piece of useful context beyond that: the dependency on Termux:API. It says nothing about blocking behavior or failure when Termux:API is unavailable.

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 front-loaded sentence with zero filler; the action and the controlling parameter lead the sentence.

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 two-optional-parameter side-effect tool with full schema coverage and a complete annotation set, this is largely sufficient. The only meaningful gap is what happens if Termux:API isn't present, which an agent might need.

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 100%, documenting both `duration_ms` (with min/max and default 300) and `force` (silent-mode override). The description adds no meaning beyond that, so baseline 3 applies.

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 device') plus the duration scope and the underlying mechanism (Termux:API). It is clear what the tool does, though it doesn't explicitly contrast with sibling output tools like notify or toast.

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?

No guidance on when to use this versus notify/toast/tts_speak, and no prerequisites stated (e.g. Termux:API must be installed). The agent must infer the usage context entirely.

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