open_app

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

No annotations exist, so the description bears full burden. It mentions using 'am' but does not disclose side effects, required permissions, error behavior (e.g., if app is not installed), or whether the tool waits for the app to start. This is insufficient for a launch action.

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?

The description is concise and front-loaded, stating the core purpose in the first sentence. Every word earns its place, with no redundancy.

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?

Given the tool's simplicity and the presence of an output schema, the description is incomplete. It lacks usage guidelines, error handling context, and permission requirements, which are critical for a tool that launches external 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?

The schema has 0% description coverage for the parameter, so the description must compensate. It provides examples of common package names, adding value beyond the bare string type. However, it does not explain how to format intent actions or what qualifies as a valid `package_or_action`.

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?

The description clearly states the tool launches an Android app or activity using 'am' (Activity Manager). It specifies the resource (Android app/activity) and the verb (Launch), making the purpose distinct from sibling tools like open_url or open_recent_apps.

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 is provided on when to use this tool versus alternatives. Siblings include open_url, execute_command, and others that could also launch apps, but the description does not offer any context for choosing open_app.

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