activate_app

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

Annotations already declare idempotent=true, destructive=false, readOnly=false and openWorld=false, so the safety profile is covered. The description adds real behavioral context beyond that: the tool mutates frontmost-app focus state, which downstream type/key calls depend on. It omits error behavior (e.g. app not found), which keeps it from a 5.

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?

A single sentence with the primary action front-loaded and the prerequisite rationale in parentheses. No 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?

For a one-parameter UI action with annotations covering safety and no output schema, the description supplies what an agent needs: what it does and why it must precede keyboard input. Minor gaps around failure modes and return behavior are acceptable given the tool's simplicity.

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?

Only one parameter exists and schema coverage is 100%, with the example 'TextEdit' documented in the schema itself. The description adds no further detail about the name argument, so the baseline of 3 applies.

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 ('Launch or bring an app to the front') with the name parameter implied. It also separates itself from the frontmost-app family by noting the ordering dependency on type/key, so an agent can distinguish it from sibling input tools.

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?

Explicitly states the condition under which this tool is needed ('needed before type/key'), which is actionable context for sequencing calls. It does not, however, describe alternatives for switching apps or when not to call it.

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