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

Annotations already establish the read-only, idempotent, closed-world profile. The description adds genuinely useful behavior beyond that: coverage is bounded by whatever cities are in the file, an out-of-file city produces an explicit 'not found' response rather than a silent failure, and the output is an estimate rather than legal advice. Return shape and formatting are left unstated, keeping this from a 5.

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 short sentences with no padding; the resource definition and its coverage boundary are front-loaded, and the disclaimer closes it cleanly. Slightly more could be said about parameter usage without bloating it.

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 three-parameter tool with no output schema, the description covers the coverage limitation and the non-advisory nature but omits the two things an agent most needs: which identifier parameter to use and what a returned digest looks like. Adequate but with clear gaps.

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 only 33% (just the slug example), and the description offers no explanation of how city, slug, and state interact or in what form a city name should be supplied. With three overlapping city-identification parameters and zero required fields, the description leaves an agent guessing which to populate, so it does not compensate for the coverage gap.

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 names a specific resource (a plain-English landlord-tenant digest) and its source (regulations.json), which is enough for an agent to know what comes back. It does not, however, distinguish itself from the many sibling lookup_* tools (lookup_covered_market, lookup_hud_rent, lookup_rent_to_income), so cross-tool routing still requires inference.

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?

There is no explicit when-to-use or when-not-to-use guidance and no mention of any alternative tool. 'Estimates for planning' hints at an intent but never states the conditions under which an agent should call this instead of, say, lookup_covered_market or lookup_hud_rent.

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