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

Annotations already declare destructiveHint=true, idempotentHint=true, and readOnlyHint=false, so the safety profile is covered. The description adds one piece of non-annotation context, the required systems:write scope, but does not clarify whether the update is partial or full replacement, or what happens to fields omitted from the request.

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 sentences with zero filler, and the core action is front-loaded ahead of the prerequisite. It is efficient, though terse enough that it leaves room to say more without becoming bloated.

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 full schema coverage and annotations covering safety and idempotency, and no output schema to document, the minimum bar is met. Still missing is any statement of update semantics (partial vs. full) or the relationship to sibling system-class tools, which matters given the very large tool surface.

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 properties (id, name, description) carry descriptions and constraints, so the schema does the heavy lifting. The description adds only the notion that the ID identifies an existing record, which is a marginal contribution over structured data.

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 ('Update an existing system class') plus the lookup key ('by ID'). However, it gives no differentiation from the numerous sibling update tools, notably update_system, update_system_group, update_project_system_class, and update_infrastructure_feature_class, which an agent could easily confuse with this one.

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?

'Update an existing system class' implies the tool only applies to existing entities and the 'Requires systems:write scope' line is a useful prerequisite. But it names no alternative (e.g., create_system_class for new records, update_system_group for grouped updates) and states no when-not conditions, leaving routing to inference.

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