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

Annotations already declare readOnlyHint=false, destructiveHint=false, and idempotentHint=false, so the mutation profile is covered. The description adds the systems:write authorization requirement, which is not conveyed by any annotation and is genuinely necessary before calling. It omits duplicate-name behavior and any indication of what the call returns, which keeps it short of 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?

Two compact sentences with the core action and its domain gloss front-loaded and a permission note at the end. Every clause carries information; there is no filler.

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 non-destructive create tool with full schema coverage, annotations covering the safety profile, and no output schema, the description covers the essentials plus the auth scope. It leaves minor gaps around whether system_class_id is effectively required in practice and what happens on a duplicate or invalid name.

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%, so all three parameters are already documented with names, types, and length constraints; baseline 3 applies. The phrase "category under a system class" loosely illuminates the optional system_class_id parent link, but no format, required/optional status, or constraint detail is added beyond the schema.

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 ("Create a new system group") and adds a clarifying gloss — a category under a system class, with examples like "Heating" and "Cooling" — which disambiguates it from create_system_class and create_system. It does not name the closely related sibling create_project_system_group, so the differentiation is contextual rather than explicit.

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?

The description gives a prerequisite ("Requires systems:write scope"), which is useful gating information, but offers no when-to-use guidance, no exclusions, and no routing to alternatives such as update_system_group or the project-scoped variant. Usage is implied by the name alone.

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