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

Annotations already establish read-only, idempotent, closed-world, non-destructive behavior, so the bar is lower. The description adds genuinely useful context the annotations lack: the fields returned, the unit semantics (measure's own unit, not money), and a data-availability constraint (history from 2026-09-20 onward).

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?

One dense sentence, front-loaded with the verb and resource, with the payload and availability details trailing. Every clause carries information; no waste.

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?

With no output schema, the description steps in to describe the return payload and its unit, plus a data-boundary caveat. For a simple single-lookup read tool with rich annotations, this is nearly complete.

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% with a single documented 'id' parameter, so the schema already carries the semantics. The description adds only the trivial 'by ID' framing, which is baseline 3 territory.

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 (Get) and resource (a single LoS targets history entry by ID) and describes the payload fields (target, minimum, stretch goal, effective_date, unit). The singular 'single ... entry by ID' implicitly contrasts with the plural list sibling, but does not name it explicitly.

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?

Usage is implied: fetch one entry when you have its ID. No when-to-use/when-not guidance, no named alternative such as list_los_targets_history, though the 'by ID' phrasing signals a direct lookup path.

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