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

Annotations already supply the safety profile (destructiveHint=true, idempotentHint=true, readOnlyHint=false), and the description adds two things they don't: the required los_targets:write scope and the fact that direction follows the metric automatically. It does not explain what is destroyed or overwritten by an update, which the destructiveHint flags but never characterizes.

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?

Three short sentences, front-loaded with the action, then the constraint, then the auth requirement. Each sentence carries information; the scale restatement (0-100 / 0-25) partially duplicates the schema's base_target description but is defensible as emphasis.

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 five-parameter mutation tool with full schema coverage, no output schema, and annotations covering safety, the description supplies what is missing: the write scope, the scale coupling between metric and base_target, and the automatic direction behavior. Nothing needed to call it correctly is absent.

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 the schema already documents every parameter including the 0-100 / 0-25 scale on base_target. The description's only added value is the cross-parameter rule tying a metric change to supplying a new base_target; that is real but marginal against a fully documented schema, so baseline 3 fits.

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+resource+identifier pattern ('Update a system LoS target by ID'), which is unambiguous on its own. It does not, however, distinguish this from close siblings such as update_infrastructure_los_target or update_los_proposed_target, so an agent with those in view gets no routing signal from the description.

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 implies usage (mutate an existing target by its UUID) and gives one useful conditional rule – send a fresh base_target when moving to a metric with a smaller scale. It never names an alternative sibling or states when this tool is the wrong choice versus update_infrastructure_los_target or create_system_los_target.

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