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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior, so the safety profile is covered. The description adds domain context about what the returned figures mean (caps at 110%/120% FMR, 90/10–60/40–30/70 blends), but says nothing about what happens on ambiguous name matches, empty results, or how `limit` truncates output.

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?

Purpose and returned fields are front-loaded in one dense sentence, followed by a compact input sentence; nothing is wasted. The enumeration of rent components is long but each item is substantive rather than filler.

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?

With no output schema, the description usefully enumerates returned fields, and annotations cover the read-only safety profile. The main gaps are result-set behavior (pagination when `limit` applies, handling of multiple PHA matches), which an agent would want for a 5-parameter search 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 coverage is 60%, and the description compensates by clarifying the conditional lookup modes: a PIC number alone, or project/pha name together with state — a combination rule the schema does not state. The `limit` parameter and its 1–25 cap remain undocumented in the description, keeping it short of a 5.

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?

States a specific verb+resource ('HUD's 2026 RAD contract rent for unconverted public housing projects') and enumerates the exact figures returned (PBV/PBRA caps, blend estimates, utility allowance, operating and tenant rent per unit month). This is clearly distinguishable from siblings like get_rad_program_facts (policy facts) and size_rad_debt (debt sizing).

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 final sentence gives input modes ('Give a PIC project number, or project/pha name with state'), which implies a lookup use case, but there is no explicit when-to-use/when-not guidance or routing to alternatives such as get_rad_program_facts or search_conversions. Usage is inferable rather than stated.

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