get_fmr_trend

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

Annotations already declare a safe read operation (readOnlyHint, destructiveHint false). The description adds useful behavioral context beyond annotations, such as the return structure (array of yearly FMR records) and the state-level limitation, which are not present in the annotations.

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 description is three concise sentences plus a source attribution. It is front-loaded with the main purpose, then returns output shape and a key limitation. Every sentence earns its place, with no redundant text.

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 read-only trend tool with no output schema and good annotations, the description covers the return format, supported geographies, the unsupported state case, and the data source. This is sufficient for an agent to select and invoke the tool effectively.

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 for parameters is 100%, so the schema already documents all four parameters. The description reinforces the area types and explains the state restriction, but does not add format examples or additional semantics beyond the schema. Baseline 3 is appropriate.

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 clearly states it retrieves Fair Market Rent data across multiple years for a single area, with specific verbs and resource. It also distinguishes itself from sibling tools by listing supported area types (ZIP, county, CBSA) and explicitly noting state-level trends are not supported.

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?

Provides clear context for when to use the tool: for multi-year FMR trends on ZIP, county, or CBSA areas. It explicitly states when not to use (state-level) and explains why, but does not name alternative sibling tools like get_fair_market_rent for single-year queries.

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