Launch Roku App

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

The description goes beyond the annotations by stating 'Changes device state (foregrounds the app)', which clarifies the real-world side effect. It also reveals that optional launch params are passed through as ECP query params, adding behavioral detail that annotations alone do not provide.

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 compact and front-loaded: the core action is stated first, followed by id discovery, side effect, alternative, and params. Each sentence earns its place with no redundant filler.

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 still fully covers what an agent needs: what the tool does, how to get valid appId values, the state-change behavior, the sibling alternative, and how params are handled. Nothing critical for correct invocation is missing.

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 baseline is 3. The description adds semantic value by explaining how to discover appId values via ecp_query and that params are passed through as ECP query params, which goes beyond the schema's bare field descriptions.

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 'Launch' and the resource 'channel / app on the device to its home screen by app id.' It also distinguishes this from the sibling deep_link by explicitly noting deep_link opens a specific title, making the tool's purpose 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?

It explicitly explains how to discover app ids via ecp_query "/query/apps", notes the special 'dev' id for sideloaded apps, and provides a clear alternative: use deep_link when opening a specific title. This gives the agent concrete decision criteria.

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