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

With readOnly/idempotent annotations already covering the safety profile, the description adds genuinely new behavioral facts: hard limits (10 trips, 10 stops, 92 days, 400 day rows), that no times are taken and same-day travel requires >12 hours, and which meal types do or do not deduct. It also discloses that worksheet downloads are produced.

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?

Three sentences, front-loaded with the operation and followed by limits and deductions; every clause carries information. It is dense with numeric constraints, but none are filler.

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 single-parameter, nested-array tool with an output schema and annotations, the description covers scope, limits, deduction rules, and exclusions, and the return format is partly handled by the output schema. Nothing essential for correct invocation 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 coverage is 100%, so the baseline is 3; the description exceeds it by disambiguating meals_provided semantics ('furnished government or registration meals reduce allowances; common-carrier meals and complimentary hotel breakfasts are not deductions') and the day-inclusive conventions that affect arrive/depart.

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 and resource ('Calculates GSA CONUS lodging and M&IE allowances for one or more trips') plus the return shape (day-by-day results with XLSX/CSV downloads). It does not name the sibling find_per_diem_rates, so the boundary between calculating and looking up rates is left implicit.

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?

Gives strong when-not coverage: bundled GSA CONUS FY2026/FY2027 only, excludes OCONUS, lodging taxes, agency policies and FY2028. It lacks an explicit pointer to find_per_diem_rates for rate lookup, so the alternative route is implied rather than stated.

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