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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the bar is lower. The description adds genuinely useful behavior: the return content (slugs plus per-area home counts) and an example showing fuzzy matching behavior ("marina" -> dubai-marina), which matters since there is no output schema.

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 sentences, zero waste. The core purpose is front-loaded and the example immediately follows, earning its place by demonstrating the fuzzy-match behavior.

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 carries the burden of describing returns and does so (slugs + counts). It leaves open edge cases such as multiple or zero matches, but everything needed to call it correctly is present.

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 100%, so baseline is 3, but the worked example (country "ae", text "marina") concretely demonstrates the expected value formats and matching semantics beyond the schema's terse field descriptions. The deal parameter's effect on counts is left to the schema.

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 transformation (place name -> area slugs) and names the sibling it feeds (search_listings), plus the extra payload (home counts per area). An agent can distinguish this from search_listings, get_listing, and list_markets without opening any 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 phrase "the area slugs search_listings filters on" clearly positions this as the prerequisite step when you have a place name but not a slug. There are no explicit exclusions or named alternatives, but the workflow context is unambiguous.

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