list_subsystem_classes

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

Annotations already declare readOnly/idempotent/non-destructive, so the safety profile is covered. The description adds real behavioral context beyond that: only loaded classes are enumerated, results split native vs Blueprint, and the exact return shape (including a breakdown count and lifetime filter echo) is spelled out. It does not mention ordering or pagination, keeping it out of the 5 range.

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 sentences, purpose front-loaded, then the return contract. Nothing is padded, and the field list earns its place because no output schema exists.

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 only one optional parameter, four covering annotations, and no output schema, the description supplies everything needed: the population (loaded classes), the variant coverage (native + Blueprint), and the return structure. An agent can call it correctly without further information.

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 schema already enumerates every legal lifetime value and states case-insensitivity. The description's 'optionally filtered by lifetime category' merely restates that, adding no syntax or semantic value beyond the schema. Baseline 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?

The description gives a specific verb ('Enumerate') and resource ('all loaded USubsystem-derived classes'), plus the scope qualifiers 'native + Blueprint'. This lets an agent distinguish it from instance-oriented siblings like list_subsystem_instances, but no sibling is actually named, so it stops short of a 5.

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 notes the optional lifetime filter, which implies when to narrow results, but never states when to use this tool versus alternatives such as list_subsystem_instances, get_subsystem_class_info, or is_subsystem_class_active. Usage is inferable but not guided.

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