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

Annotations already declare readOnlyHint=false, destructiveHint=true, and idempotentHint=true, so the safety profile is largely covered. The description adds real value with the required write scope, which annotations do not express. It stops short of explaining partial-update behavior or what happens to unspecified fields, so it is adequate but not rich.

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 purpose and followed by the constraint. Nothing is wasted, though it is almost too terse for a four-parameter mutation tool.

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 mutation tool with no output schema and strong annotation coverage, the description supplies purpose, the ID-based target, and the permission requirement. Missing only update semantics (partial vs full) and any routing versus sibling LoS target tools, which the rich annotation set partly offsets.

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 id, year, target_value, and target_statement with ranges and units. The description adds no parameter-level meaning beyond that, so the 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?

The description states a specific verb and resource ('Update an existing LoS proposed target') plus the targeting key ('by ID'), so an agent knows exactly what entity is being mutated. It does not, however, distinguish itself from the many near-neighbor update tools such as update_los_measure, update_los_consequence, or update_infrastructure_los_target.

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 only guidance offered is a permission prerequisite ('Requires los_proposed_targets:write scope'), which is not a when-to-use signal. There is no statement of when this tool is appropriate versus update_infrastructure_los_target, update_system_los_target, or the bulk_update/create siblings, leaving alternative selection entirely to inference from the name.

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