Build, install and launch

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

With no annotations, the description carries the full burden; 'Runs as a job' is a valuable disclosure that the call is asynchronous and returns before completion. However, it does not say what the job handle looks like, that job_status must be polled, that it mutates device state, or what happens on build failure or when multiple devices are attached.

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?

Two tight sentences, front-loaded with the conceptual anchor, zero filler. Every clause earns its place by naming the three concrete steps and the async execution model.

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 five-parameter, zero-required, no-annotation, no-output-schema tool, the description should at least say what comes back (a job identifier) and how to continue/poll. The 'Runs as a job' line gestures at this but leaves the return contract and multi-device selection behavior unexplained.

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 coverage is 60%: serial, waitSec and projectDir are documented, but module and variant are bare. The description only obliquely touches 'variant' via 'assemble the variant' and says nothing about 'module', so it does not compensate for the two undocumented parameters and adds no format or defaulting semantics.

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 concrete composite verb chain (assemble → install → launch launcher activity) tied to a recognizable metaphor, the Android Studio 'Run' button. An agent can tell this is a one-step build+install+launch rather than any single sibling, though the description never explicitly contrasts with build/app_install/app_launch.

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 'Run button' framing implies when to use it (full end-to-end deploy), but there is no explicit guidance on when to prefer the granular siblings (build, app_install, app_launch) or on prerequisites such as a device being online or a synced project. Polling guidance lives only in the waitSec schema field.

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