phone_launch_app

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

Annotations already declare destructiveHint=true, idempotentHint=false, and openWorldHint=true, so the safety profile is covered structurally. The description adds the mechanism detail that launching goes through the launcher activity, but says nothing about non-idempotency, failure when the package is absent, or that it brings an activity to the foreground.

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 tight sentence with the action front-loaded and zero filler. Every clause carries 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 no explanation, and annotations cover the safety hints. However, with a 0%-covered 2-param schema the description leaves the serial parameter and the package identifier format undocumented, and gives no hint about failure modes for uninstalled apps.

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 0%, so the description must carry the load. It names the 'package identifier' concept matching the required package param, but omits the required dotted-identifier format and never mentions the serial parameter at all, leaving multi-device targeting unexplained.

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 (launch), a specific resource (an installed app), and the mechanism (package identifier / launcher activity). It is clearly distinguishable from siblings like phone_list_apps, though it never names an alternative explicitly.

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 phrase 'installed app' hints at a precondition, but there is no statement of when to use this versus phone_list_apps (to discover packages) or the tap/observe tools, and no when-not guidance. Usage must be inferred entirely from the verb.

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