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

Annotations already declare a safe, read-only, idempotent, closed-world operation, and the description goes well beyond them: it discloses the estimate's assumptions (dependent status held constant), the completeness flag totalIsExact=false with incompleteReason, how reconstructed vs published rate tables are handled, and the 38 CFR 3.31 payment-start and payment-year rules. This is unusually rich behavioral context.

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?

The single-sentence trigger is front-loaded and the flow is logical, but the body is dense with regulatory mechanics and per-field output detail (rateYear, rateTableEffectiveDate, rateSource, rateTables) that could be tightened. Nearly every sentence is informative, though the length is near the limit of what an agent needs.

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 carries the full burden of explaining returns, and it does: per-month breakdown, assumptions, disclaimer, rate-table provenance, and the exactness flag. Combined with the refusal conditions and rate-source rules, an agent has everything needed to call and interpret the result.

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 every parameter (effectiveDate, fromRating, toRating, hasSpouse, dependentCount, isTdiu, adjudicationDate) is already documented in the schema. The description adds usage-level context for effectiveDate (pre-1990 refused, payment timing) but no new syntax or constraints for the remaining inputs, 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?

States a precise verb and resource ('estimate retroactive back pay') and scopes it tightly: a veteran-supplied effective date plus a rating increase. It explicitly distinguishes itself from rate-lookup work by clarifying it 'does not set an effective date and it does not report an amount VA has authorized,' so an agent can route it apart from lookup_compensation_rate.

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?

Opens with an explicit trigger ('Use this when a veteran gives an effective date and a rating increase and asks what the retroactive amount would be') and supplies exclusion conditions: it handles increases only, requires the new rating to be higher, and refuses effective dates before 1990. The applicability envelope is fully specified.

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