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

Annotations already declare readOnlyHint=true, and the description adds useful behavioral context: data source (FRED weekly survey), update frequency ('Rates update weekly'), and pricing ('$0.02 USDC per call'). It goes beyond annotations without contradicting them.

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 a single sentence that front-loads the core purpose, then lists data points, audience, update frequency, and cost. It is compact and free of filler, though slightly dense. Splitting into two sentences could improve readability, but no content is wasted.

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 benchmark tool, the description covers source, content, update cadence, cost, and audience. However, it lacks any explanation of how the optional state and loan_type parameters work, and no output schema exists, so an agent cannot fully predict the response shape or filter behavior. This leaves notable completeness gaps.

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 0%, and the description does not explain how 'state' or 'loan_type' affect the benchmark data. The parameter names are somewhat self-explanatory and the enum for loan_type is in the schema, but the description adds no additional meaning about filtering, required values, or output variation. This leaves a significant gap for an agent.

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 identifies the resource as 'Live mortgage rate benchmarks' and enumerates specific data components (30Y/15Y fixed from FRED, ARM spreads, points/fees, DTI, affordability index). This makes the tool's function highly specific and distinguishes it from sibling benchmarks like get_rental_market_benchmark or get_residential_market_benchmark.

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?

The description states an intended audience ('For homebuyers, lenders, real estate agents, and housing analysts') but does not explicitly mention when to choose this tool over related siblings. There is no contrast with similar benchmark tools or exclusion criteria, so usage guidance remains implicit rather than explicit.

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