Launch an app by package id

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

Annotations establish the safety profile (not read-only, not idempotent, not destructive), and the description adds real behavioral context beyond that: the underlying resolve-activity/am start -n flow, the -W wait semantics, and the fact that it returns the resolved component for reuse. It does not cover auth or rate constraints, but none are implied here.

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?

Three sentences, front-loaded with the core action, and each sentence carries routing or mechanism value. The 'monkey' aside earns its place as a justification against the shell path.

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?

With no output schema, the description compensates by disclosing the return value (the resolved component) and the reuse path via start_activity. For a 4-parameter launch tool, this is nearly complete, missing only edge-case behavior on unresolvable packages.

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 100%, so the schema already documents all four parameters including wait, device, and timeout_ms. The description's '-W when wait is true' restates the schema's own semantics rather than extending them, 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+resource (launch an installed app by package id) and reveals the mechanism. It explicitly distinguishes itself from siblings start_activity and shell, so an agent can select it without opening the schema.

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?

Clear routing context: it returns the resolved component so later calls can use start_activity, and it argues for itself over the 'monkey -p' shell one-liner. It lacks an explicit 'when not to use' statement but the alternative relationship is clear.

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