launch_app

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

With no annotations, the description carries the behavioral burden, and it does disclose substantial behavior: launch confirmation is actually verified, the result carries the NEW window dict, and the screen-locked fallback returns a new AT-SPI app while naming the confirming mechanism. It could add failure behavior, but the core side effects and return semantics are clear.

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 only two sentences. The first sentence leads with the action and immediately gives the confirmation contract; the second gives the use-case context. Every clause carries useful information, with no padding.

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 lack of an output schema, the description usefully describes result contents, including the locked-screen behavior. It also signals the protocol-native intent. It does not detail failure/timeout behavior, but the schema's timeout min/max/default partially fills that gap, so overall the tool is usable for first-step launch tasks.

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 at 80%, and the schema already explains file, command, desktop_id, and wait_window, including the exact-one constraint between desktop_id/command. The tool description adds no per-parameter meaning beyond that, so the agent has adequate but not enriched parameter semantics.

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 states a specific verb and resource: 'Start an application and confirm it actually arrived.' It also clarifies what makes this tool distinct from listing or activating apps: it handles the case where the app is not running yet, and it reports the NEW window or AT-SPI app that confirms launch.

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?

It gives clear context: 'Every real task starts with an app that is not running yet; this is that step.' The phrase also positions launch_app as the protocol-native replacement for shell-launching, so an agent knows when to reach for it. It does not explicitly name sibling alternatives, but the use-case signal is strong.

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