hmda_rate_spread

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

The readOnlyHint annotation already signals a safe read/calc operation, so the description does not need to repeat that. It adds useful context about the formula and external CFPB calculator, but does not disclose additional behavioral traits such as rate limits or error handling. This is acceptable given annotation coverage.

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 two sentences, front-loaded with the main action, and each sentence earns its place: the first states what it does, the second adds the formula and usage context. No filler or redundancy.

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 tool is a straightforward calculator with all parameters documented in the schema, the description is mostly complete. It defines the calculation and its purpose, though it does not state the return format, which an agent might infer. Still, for a simple calculation tool, this is sufficient.

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?

The input schema covers 100% of parameters with descriptive details, so the baseline is 3. The description adds only the conceptual formula (APR vs APOR) but does not elaborate on individual parameter formats or constraints beyond what the schema already provides.

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 calculates the rate spread for a mortgage loan, names the specific CFPB calculator, and provides the formula (APR minus APOR). It distinguishes itself from sibling HMDA tools like hmda_validate_uli and hmda_check_digit by focusing solely on rate spread calculation.

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 provides context for when to use the tool ('Used for HMDA reporting and fair lending analysis'), indicating relevant use cases. It does not explicitly exclude alternatives or mention other tools, but the purpose is specific enough that the usage is clear.

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