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

Annotations already cover the safety profile (readOnlyHint, destructiveHint=false), and the description adds genuinely non-obvious behavior: bundled fiscal years are served from GSA files with no API call, and AK/HI/territories return a pointer to DoD/State rates rather than an empty list. That last point is exactly the kind of edge-case behavior an agent needs; it only lacks error/permission notes to reach a 5.

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?

Front-loads the core action in the first line, then layers return-shape and edge-case detail in a logical order with no filler. Slightly long for a two-parameter lookup, but each sentence contributes information.

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, yet the description still usefully sketches the return shape (cities/counties, state standard rate, lodging_by_month). With annotations covering safety and the output schema covering structure, the only real gap is the unspecified state input format.

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 0%, so the description must carry parameter meaning, but it only indirectly gestures at 'fiscal year' via the bundling note and never specifies the accepted format for 'state' (2-letter code vs. full name). The fiscal_year default and valid range are left entirely to the schema's type/default.

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 ('Get all Non-Standard Area (NSA) per diem rates for a state') and makes the scope explicitly state-wide, which implicitly separates it from the city/zip siblings. An agent can tell what it returns and at what granularity without opening the schema.

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 concrete use cases ('comparing rates across cities within a state', 'building a travel IGCE with multiple destinations') that establish when this tool is appropriate. It does not name a specific alternative sibling (e.g., when to prefer lookup_city_perdiem or compare_locations), so it falls short of explicit routing guidance.

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