Install an APK

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

With no annotations, the description carries the full burden and does disclose two meaningful behaviors: it updates an existing install rather than failing, and it grants the APK's permissions automatically — a security-relevant side effect not visible in the schema. It omits failure modes, whether the device must be unlocked/connected, and whether the install is reversible.

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 short sentences, front-loaded with the core action and the side effect, then the optional launch behavior. Nothing is wasted.

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 mutating tool with no annotations and no output schema, the description covers what the tool does and the permission side effect but leaves out what happens on failure, multi-device behavior beyond the schema hint, and whether any confirmation or cleanup is needed.

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%, so all three parameters are already documented, and the description's note about `open` largely restates the schema's 'Package name to open after installing'. It adds no detail on `apk` path expectations or how `serial` selects among devices.

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 (install/update an APK from this computer) and notes the post-install launch option, which lightly separates it from phone_open. It doesn't name siblings explicitly, so an agent must still infer the boundary with phone_open and phone_app.

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?

Usage is implied by the install/update framing and the note to pass `open` to launch afterwards, but there is no explicit when-to-use versus when-not guidance or statement that phone_open should be used for already-installed apps.

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