is_subsystem_class_active

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

Annotations already cover the safety profile (readOnlyHint, idempotentHint, non-destructive), so the bar is lower, yet the description adds genuine behavioral detail: it checks all five lifetime categories and sets active=true if an instance exists in ANY of them, and reports which collection each came from. This describes the evaluation logic rather than repeating annotations.

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?

Front-loaded with the purpose and the sibling contrast before the return shape. Two sentences, both earning their place, though the '--' em-dash construction is slightly loose.

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?

Despite having no output schema, the description supplies the return shape ({ class_name, lifetime, active, instances:[{ collection, instance_path }] }), closing the gap. Combined with the input schema and annotations, an agent has everything needed to call and interpret the tool.

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% and the single parameter's description ('Short class name or /Script/ path') already documents accepted formats. The description reinforces the singular 'ONE named class' constraint but adds no syntax or format detail beyond the schema, so the baseline 3 is appropriate.

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 ('Probe whether ONE named USubsystem class currently has a live instance') and explicitly frames it against the sibling enumeration tool (list_subsystem_instances). An agent can distinguish the yes/no probe from the list operation without opening either schema.

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?

Names the alternative (list_subsystem_instances) and characterizes the selection condition ('the yes/no question, where list_subsystem_instances is the enumeration'). Clear routing context, though it stops short of an explicit when-not statement.

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