launch_app

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

Annotations already declare destructive/openWorld/non-idempotent/not-readOnly, so the safety profile is covered. The description adds value beyond that: it discloses the default window-reuse behavior and that the call returns a window selector. It still doesn't explain the high-risk confirmation_token flow that the schema hints at.

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?

Three dense sentences with no filler, and the primary action plus default behavior are front-loaded. Every sentence carries operational content, though the Browser MCP sentence could be tightened.

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?

With 8 parameters and no output schema, the description correctly surfaces the return value ('return a window selector') and the key default. Given full schema coverage, most parameter detail is handled structurally; the main remaining gap is sibling differentiation from open_app.

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% across 8 parameters, so the schema already carries parameter meaning. The description largely restates the reuse_existing/new_window semantics that the schema already documents, adding little parameter-level meaning beyond baseline.

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 and resource ('Open or launch an app through Hyprland and return a window selector'), so the agent knows exactly what it does. It does not distinguish itself from the sibling open_app, which appears to overlap, leaving some ambiguity about which launch-family tool to pick.

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?

Gives explicit conditional guidance: reuse is the default, and reuse_existing=false is only for an explicit new-instance request. It also carves out the Browser MCP boundary ('use this instead of Browser MCP only when an app launch/open is requested'). It omits any guidance relative to the sibling open_app.

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