launch_app

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

With no annotations provided, the description fully carries the behavioral transparency burden. It states the launched activity type, success indicator (echo component), and error conditions (missing package or launcher). The usage pattern with stop_app adds transparency about side effects and state management.

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 (three sentences), front-loaded with the main action, and every sentence adds value. No filler or redundant information. It efficiently conveys purpose, behavior, and usage.

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 simple tool with no output schema and good parameter documentation, the description is largely complete. It covers success/failure behavior and a common usage pattern. Minor gap: the output format ('echo') is implied but not explicitly defined.

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 baseline is 3. The description does not add meaning beyond what the input schema already provides for the two parameters (package and serial). No additional context about parameter values or constraints is given.

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's purpose: 'Launch an app by package name (starts its LAUNCHER activity) and echo the resolved component on success.' It uses a specific verb-resource combination and distinguishes itself from siblings like stop_app by explaining how to combine them for a clean restart.

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 description provides explicit guidance on when to use the tool and what to expect on failure ('Fails with a clear message when the package isn't installed or has no launcher activity'). It also suggests a common workflow with stop_app, though it doesn't explicitly mention alternatives for deep links or other launch methods.

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