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

Annotations already declare the safe read-only, idempotent, closed-world profile, so the description only needs to add context — and it does: it discloses the return contents (per-tax amount plus who customarily pays seller/buyer/negotiable), the total, exclusion flags (NYC supplemental tax, local municipal taxes), and a liability caveat ('An estimate, not tax advice'). Only pricing/rate-limit or freshness behavior is absent, which is minor here.

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?

Two tight paragraphs with the purpose front-loaded, then parameters, then returns. The long place enumeration is dense but each token is load-bearing given 0% schema coverage; little waste.

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 and 0% param coverage, the description compensates by enumerating inputs and describing the return shape, exclusion flags, and source attribution. An agent has everything needed to call it 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?

Schema description coverage is 0%, so the description carries the full burden and does so completely: it defines place with a concrete value list and aliases, price as consideration in dollars, kind as residential/other with its NYC impact, and mortgage as Florida-only with the specific taxes it triggers (note stamps, intangible tax). No optional/required distinction is stated, but otherwise nothing is left ambiguous.

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 ('Real estate transfer taxes on a sale') and names the source basis ('from the statutes and tax offices'), which cleanly separates it from the recurring-rate siblings like property_tax_rate_by_county. An agent can identify this as a one-time transaction tax calculator without opening the schema.

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 `place` enumeration scopes usage precisely (nyc vs ny vs fl vs philadelphia/chicago/cook, plus state/city names), and conditional rules are given per parameter ('kind: NYC rates differ', 'mortgage: Florida only'). It never names an alternative to route to, so it stops short of full when-not guidance.

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