Launch the League of Legends client

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

The annotations already declare idempotent, non-destructive, and open-world behavior, so the description's 'Safe and idempotent' line is largely redundant. However, it adds useful operational context: avoiding duplicate processes, optionally polling for LCU readiness, and the installation prerequisite.

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 front-loaded with the core action and remains compact. The standalone 'Behavior: Safe and idempotent' sentence is somewhat redundant with the annotations and the preceding sentence, but the overall structure is efficient.

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 launch tool with no output schema and rich annotations, the description provides the missing context an agent needs: launch mechanism, optional readiness polling, duplicate-process handling, and the installation prerequisite. Nothing essential for correct invocation appears to be 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 description coverage is 100%, and all three parameters are already well documented in the schema. The description reinforces the optional wait behavior and executable choices, but adds no syntax, format, or constraints beyond what the schema provides.

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: launching the League of Legends client via named executables. It also distinguishes the tool from diagnostic and automation siblings by focusing on process launch and LCU readiness.

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 provides a clear prerequisite (League must be installed) and explains the already-running case, which effectively tells the agent when the tool is needed. It does not name alternative tools, but no sibling appears to offer the same launch capability.

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