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

Annotations already declare destructiveHint=true, idempotentHint=true, and openWorldHint=false, so the safety profile is covered structurally. The description contributes the required auth scope, which is genuinely useful, but says nothing about partial-update semantics or what happens to fields left out.

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, front-loaded with the action and then the precondition; no filler. It is perhaps overly terse for a mutation tool, but nothing 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?

For a four-parameter mutation tool with full annotation coverage and full schema coverage, the description is minimally viable. The notable gap is whether unspecified fields are left untouched or cleared, which matters for an idempotent, destructive 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%, with each of the four fields (id, name, description, system_class_id) documented in the schema, so the baseline is 3. The description's 'by ID' adds nothing beyond the schema's required id field.

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 group) and identification method (by ID), so the operation is unambiguous. It does not distinguish itself from close siblings like update_system, update_system_class, or update_project_system_group, which the name alone is left to carry.

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 states a prerequisite (systems:write scope) but gives no guidance on when to choose this tool over update_system_class or update_project_system_group, nor when updating is preferable to recreating. Prerequisite info is not the same as usage guidance.

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