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

Annotations already declare readOnlyHint=false, idempotentHint=true, destructiveHint=true and openWorldHint=false, so the mutation/modifier profile is covered. The description adds the authorization requirement, which is not in the annotations. However it never explains partial-update semantics (whether omitted fields are preserved or cleared) or what makes this 'destructive', which is the natural concern raised by destructiveHint=true.

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, no filler, with the identifier and scope requirement front-loaded. Nothing could be trimmed without removing information.

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 an idempotent, destructive update tool with full schema coverage and no output schema, the essentials are present (resource, keying, auth). What is missing is the update semantics that an agent must know before calling: whether this is a partial patch, and what the destructive behavior entails.

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% with all four parameters documented, so the baseline is 3. The description only reinforces the required 'id' ('by ID') and adds nothing about name, description, or system_class_id usage or their update semantics 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 plus resource ('Update an existing system group by ID'), which is clearly distinguishable from create_system_group/delete_system_group and from update_system/update_system_class. It stops short of differentiating itself from adjacent update siblings beyond what the resource name already implies.

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 supplies one real usage constraint ('Requires systems:write scope'), which is genuinely useful for deciding whether the call can succeed. It gives no when-to-use/when-not guidance relative to the sibling update tools or prerequisites such as needing an existing group ID from list_system_groups.

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