Launch Roku App

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

Annotations already declare readOnlyHint=false, idempotentHint=false, destructiveHint=false, so the safety profile is known. The description adds valuable context: it changes device state (foregrounds the app) and passes launch params through as ECP query params, which is not present in annotations. This goes beyond the structured data.

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?

Two sentences, front-loaded with the core action, then immediately addresses the alternative and param behavior. Zero filler, every clause earns its place.

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 description covers purpose, state change, alternatives, and param handling. It omits error conditions and edge cases, but for a launch tool with a single required parameter, this is sufficient. No output schema is present, but the return value is likely trivial and not essential for correct invocation.

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 all parameters are documented, but the description adds meaning: appId can be discovered via ecp_query, 'dev' is a specific sideloaded app, and the params object is passed through as ECP query params. This enriches understanding beyond the schema definitions.

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?

States a specific verb (launch) and resource (channel/app by app id) with a clear goal (home screen). Explicitly differentiates from the deep_link sibling by naming it and the condition for using it. Purpose is unmistakable.

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?

Provides explicit guidance on when to use this tool versus deep_link, and how to discover app ids via ecp_query. The description fully covers selection criteria and prerequisites, leaving no ambiguity.

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