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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint=false and destructiveHint=false, so the safety profile is fully covered. The description adds valuable behavioral detail: the result set is limited to markets that actually have snapshots, and output shape branches on which parameter is supplied. It does not say what an empty result means (no coverage vs. bad input) or what the 'overview' contains.

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, front-loaded with what the tool returns and followed by the parameter-driven behavior. No filler, no restatement of the title or annotations.

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 does the necessary work of explaining that results are constrained to markets with snapshots and how the return set varies by parameter. Minor gaps remain around what 'overview' returns and whether unmatched business types error or return empty.

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 the schema documents the country enum-like list and business_type examples. The description goes beyond that by explaining the interaction contract — business_type yields its cities, country narrows either list, neither gives an overview — which the schema alone does not convey.

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 resource — business types and cities that have snapshots — which tells an agent this is an enumeration/coverage-listing tool. It implicitly distinguishes itself from get_local_market_snapshot (which retrieves data) and find_businesses_without_website, but never names either sibling, so the routing is inferred rather than explicit.

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 second sentence spells out three concrete invocation modes: pass a business type to get its cities, pass a country to narrow either list, or pass nothing for an overview. That is clear usage context, but there are no exclusions or guidance on when to prefer a sibling tool instead.

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