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

Annotations already declare non-read-only, non-idempotent write behavior, so the safety profile is covered. The description nonetheless adds genuine behavioral context beyond the schema: the 409 duplicate response, the required los_targets:write scope, and the criticality-modifier derivation logic for scoring. It does not describe the response body, but that gap is minor against annotations that already flag the write semantics.

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?

Front-loaded with the purpose sentence, then constraints in a logical order. Dense but nearly every sentence carries load; the arithmetic illustration of the modifier is helpful but slightly heavy.

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?

No output schema exists, yet the description covers purpose, idempotency/error behavior, scope requirement, prerequisite lookup, metric semantics, and the derived-target model. An agent has enough to call it correctly without further inference.

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 coverage is 100%, so the schema already documents all four parameters and the baseline would be 3. The description goes further by explaining metric direction (higher- vs lower-is-better), why direction cannot be sent, and each metric's scale, which adds interpretive meaning beyond the raw enum.

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 (Set) and resource (technical Level of Service target) scoped to one system and metric. It implicitly distinguishes itself from sibling create_infrastructure_los_target and create_los_proposed_target by naming the system-level, base-target nature of the row.

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?

Explicitly states the one-per-system-and-metric constraint, tells the agent that a duplicate returns 409 and to update the existing row instead (naming the alternative path), and gives a prerequisite ('Resolve system_id first via list_systems'). Both when-to-use and when-not are covered.

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