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

Annotations already declare readOnly, idempotent, non-destructive, closed-world, so the safety profile is covered. The description adds genuine behavioral context beyond that: the returned field set, the explicit exclusion of mystery test data and internal notes, and the certified/unverified-level rule.

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?

Front-loaded with the core verb/resource and lookup keys, followed by dense, information-bearing sentences about the response. Only slight redundancy between the description's key list and the schema's identical parameter description.

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 carries the return-value burden by naming the response fields and exclusions. Zero required parameters is not addressed (what happens when nothing is supplied), but otherwise the agent has enough to call it correctly.

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% and the schema already tells the agent that 'id' accepts a listing id, slug, domain, or website URL. The description largely restates that, adding no new syntax or format guidance, so the baseline 3 applies.

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 and resource ('Fetch one public listing') and enumerates the accepted lookup keys (id, slug, domain, website URL). It distinguishes itself implicitly from search_businesses by being a single-entity lookup, but never names the sibling, so it stops short of a 5.

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 multiple lookup keys imply 'use this when you already have an identifier' versus search_businesses for discovery, but the routing is left to inference. No explicit when-not or alternative tool is named.

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