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

With no annotations, the description carries full behavioral burden, and it does this well by disclosing the historical CFPB HMDA 2025 source, the filter criteria, that shares need not sum to 100 because reasons are not a partition, and that it is not a prediction about any individual application.

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 densely informative but well organized into ANSWERS, PARAM, NOT FOR, and source/attribution sections. Every sentence adds value, and the key usage guidance is front-loaded.

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 simple one-optional-parameter tool with no output schema, the description fully explains the return shape, scope, data source, and important caveats. An agent has enough context to invoke it correctly and interpret the result.

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 schema already documents the lender parameter at 100% coverage, so the baseline is 3. The description adds useful semantic guidance beyond the schema by explaining that omitting the lender produces cross-lender medians, which helps an agent call the tool correctly.

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 identifies a specific resource ('denial reason shares'), a data scope (95 of 100 largest lenders reporting HMDA denial reasons), and concrete output (median and maximum share per reason plus the highest-share lender). It also disambiguates itself from application-level questions with 'NOT FOR: why a particular application was denied.'

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 gives a clear when-to-use signal by listing the questions it answers and explicitly saying the optional lender should be omitted for cross-lender medians. It also states a clear not-for case, though it does not name specific alternative sibling tools.

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