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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description adds the analytical framing (age held constant, changes vs average) but says nothing about data limitations, coverage gaps, or how missing schedules are handled; with annotations carrying the behavioral burden, this lands at an adequate 3.

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 sentences, front-loaded with what it returns before the usage cue, with no filler. The mid-sentence catalogue of outputs is dense but each item is informative, so it earns its length.

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?

An output schema exists, so return values need not be explained, yet the description anticipates the agent's needs by naming the per-schedule and aggregate figures it produces. Combined with annotations for the safety profile and the schema for parameter formats, nothing essential is missing.

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 75% and the schema already documents cert, gender and smoker. The description only implicitly clarifies the age parameter ('the premium at this age ... with the age held constant'), which is useful but shallow; the baseline 3 is appropriate when the schema does most of the work.

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 names a specific resource (a plan's premium record) and enumerates exactly what it returns: each filed schedule, the premium at a held-constant age, year-on-year changes, and the average. It also scopes the data with 'since 2021', which meaningfully separates it from sibling tools like insurer_increases and estimate_renewal.

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?

It gives concrete use cases in the insurer's own question form ('has this gone up', 'is this insurer stable'), which tells the agent when a historical-record read is the right call. It stops short of naming alternatives or stating when not to use it (e.g. versus insurer_increases for insurer-level trends), so it isn't a full 5.

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