open_app

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

With no annotations, the description carries the transparency burden. It discloses that the app name is checked against installed apps before launching and that the tool waits for the foreground state, which is valuable behavioral context. It does not mention error handling when the app is not found, but the core behaviors are covered.

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 well-structured with an opening sentence, a short paragraph on accepted formats, and an Args section. It is concise but somewhat redundant with the schema parameter descriptions. Front-loaded purpose and clear layout justify a 4.

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?

The tool is simple and the description covers the main flow: name resolution, validation against installed apps, and waiting for foreground. An output schema exists, so return values need not be explained. Missing details like failure modes are minor given the tool's scope.

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 already documents both parameters fully (100% coverage). The description repeats similar information but adds the explicit acceptance of variations like 'YouTube' and 'play store', slightly enhancing the semantic clarity. This is marginal beyond the schema, so baseline 3 is appropriate.

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 verb ('Bring an app to the front') and the resource (an app), and specifies accepted input formats (natural names, package IDs). It does not explicitly contrast with sibling tools like open_url, but the purpose is unambiguous.

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 implies when to use the tool (when you need to open an installed app) but does not mention alternatives or exclusions. It lacks guidance on when to use open_url or list_apps instead, leaving the selection to inference.

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