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

The description adds the auth prerequisite (systems:write), which annotations do not convey, and that is genuinely useful. However, annotations already declare destructiveHint=true and idempotentHint=true, and the description does not explain what makes this destructive or whether omitted fields (name/description) are cleared or preserved — a meaningful gap for a mutation tool.

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 no filler, front-loading the action and following with the permission requirement. Lean to the point of leaving behavioral questions unanswered, but nothing in the text is wasted.

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?

Covers identity, action, and authorization, which is the minimum for a three-parameter mutation tool, and no output schema exists to explain returns. Still missing update semantics (partial vs full replacement, effect of omitted fields), which an agent needs before invoking a destructive-flagged update.

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 (id, name, description) are self-documented with types, formats, and length bounds. The description only restates "by ID" and adds no syntax or semantic detail beyond the schema, so 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?

Specific verb (update) plus resource (system class) plus the keying field (by ID). An agent can distinguish it from create_system_class / delete_system_class / update_system_group on name and verb alone, though the description does not name those siblings explicitly.

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 by ID" implies the tool operates on an already-persisted record rather than creating one, and the scope requirement signals a permission precondition. Beyond that there is no explicit when-to-use vs when-to-use-something-else guidance or exclusion.

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