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

Annotations already declare readOnlyHint=true, openWorldHint=false, idempotentHint=true, and destructiveHint=false, so safety is covered. The description adds useful behavior context beyond annotations: it names the returned data domains, HUD inspection scoring types, Section 8 contract details, and that results include HUD as-of dates and sources.

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 front-loaded sentence beginning with the action and key identifier. It is dense but every clause describes a concrete returned data category, so it is appropriately sized for a rich lookup response, though it could be easier to scan if split.

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?

There is no output schema, so the description carries the burden of explaining return values, and it does so thoroughly: all HUD-published fields, years left, property URL, inspection history with scoring types, and Section 8 contracts with as-of dates and sources. Combined with complete parameter schema and read-only annotations, an agent has enough context to call and interpret the tool.

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 description coverage is 100%, and the schema already documents fha_number as an '8-digit HUD project number, e.g. 17635050.' The description restates the same format but adds no syntax, validation, or lookup edge-case guidance beyond the schema, so the baseline of 3 applies.

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 states a specific verb and resource: 'Look up one loan by its 8-digit HUD project (FHA) number.' It also clarifies scope as a single-loan lookup, which implicitly distinguishes it from the sibling search_loans tool, but it does not explicitly name or differentiate against siblings.

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?

Usage is implied by 'Look up one loan by its 8-digit HUD project (FHA) number,' meaning the agent should use it when it already has an FHA number. However, it does not state when to prefer search_loans, nor does it include exclusions, prerequisites, or failure conditions.

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