system_activate_app

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

Annotations already declare destructiveHint=false, idempotentHint=true, and openWorldHint=true, covering the safety profile. The description adds 'permissions: none' and the 'running' precondition, but does not disclose what happens if the app is not running (error vs. launch) or any side effects of bringing an app to the foreground.

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 short clauses, front-loaded with the action and resource. The bracketed metadata '[v1.0.0; permissions: none]' is slightly noisy but compact and does convey a permission fact.

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?

An output schema exists, so return values need no explanation. Still, for an open-world mutation-ish tool with a required idempotency key and an approval mechanism, the description omits the failure mode when the app is not running and any mention of the approval flow required by _approvalId.

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 (bundleId, _idempotencyKey, _approvalId) are documented in the schema, so the baseline is 3. The description only echoes the bundleId concept and adds nothing about the required idempotency key or the approval ID.

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 ('Activate') and resource ('a running application') qualified by the identifier type ('by bundle ID'), so the action is unambiguous. It does not explicitly name or contrast with the closest sibling, system_open_app, leaving the activate-vs-launch distinction to inference from 'running'.

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?

'Activate a running application' implies the precondition that the target is already running, which is useful context. However, it never states when to choose this over system_open_app (which presumably launches a non-running app) or what to do if the app is not running, so routing guidance is only implied.

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