US Mortgage Rate Decision

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

Annotations already provide readOnlyHint, destructiveHint, idempotentHint, and openWorldHint. The description adds behavioral context by specifying that it returns recommended actions, APR, payments, and confidence scores, and covers 4,300+ lenders. No contradictions.

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 concise sentences with front-loaded purpose. First sentence states the core function, second lists outputs and supported products, third mentions filtering. No unnecessary words.

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?

Given the rich annotations and 100% schema coverage, the description covers all necessary aspects: purpose, outputs, supported products, and filtering. An output schema exists, so return values need no further explanation. The tool is adequately described for selection.

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% with parameter descriptions. The description reinforces and contextualizes the parameters by mentioning filtering by state, amount, and credit tier, and supporting 30yr/15yr/ARM products. It adds value beyond the schema.

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 the tool's purpose: getting AI-powered mortgage rate decisions from US lenders, listing specific outputs (APR, monthly payments, confidence scores) and supported products (30yr/15yr fixed, ARM). This distinguishes it from siblings like auto, heloc, personal lending tools.

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 implicitly indicates use for mortgage rate decisions but does not explicitly state when to use this tool versus alternatives or when not to use it. The sibling tools (auto, heloc, personal) are different but no direct comparison is made.

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