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

Annotations already establish a safe, read-only, idempotent profile, and the description goes well beyond that with domain behavior: the 38 CFR 3.31 payment-start rule, the December 1 payment-year boundary, pre-2000 tables reconstructed via the SSA COLA chain, months past the newest table served from the newest available with totalIsExact=false and incompleteReason, and the constant dependent-status assumption that makes the total an estimate. These are the operational caveats an agent needs and none are derivable from annotations or schema.

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?

Usage and the key exclusions are front-loaded, and most sentences carry real load — especially the return-shape details, which are load-bearing because there is no output schema. It is nonetheless a dense single block of roughly 330 words covering rate-table mechanics that could be tightened.

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 accepts the burden of describing the return: per-month breakdown, rateYear, rateTableEffectiveDate, rateSource, rateTables, totalIsExact, incompleteReason, assumptions, and disclaimer. Combined with the coverage rules and refusal conditions, an agent has everything needed to call and interpret it.

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 baseline is 3; the description adds some meaning on top, notably that dependent status is treated as constant across the period and that the tool acts on a rating increase (fromRating must be below toRating). It does not, however, add format or boundary detail for adjudicationDate or isTdiu beyond what the schema already states.

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 opens with a precise verb+resource ('estimate the retroactive amount') tied to a concrete trigger: a veteran supplying an effective date and a VA rating increase. It is clearly distinguishable from siblings like calculate_combined_rating or lookup_compensation_rate, which do not model a retroactive period.

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 states exactly when to use it ('when a veteran gives an effective date and a VA rating increase and asks what the retroactive amount would be') and carves out explicit non-uses: it does not set an effective date and does not report an authorized amount. It further bounds usage by noting it handles increases only (new rating must exceed the previous one) and refuses effective dates before 1990.

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