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

Annotations already declare readOnlyHint and idempotentHint. The description adds that every fact is published on the public website, signaling that data is public, stable, and non-sensitive. This is useful behavioral context beyond the annotations, with no contradiction.

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 compact sentences with no filler. The first sentence front-loads the resource and content scope; the second adds provenance and a clear usage instruction. Every word earns its place.

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 zero-parameter, read-only, idempotent lookup, the description is complete: it states what data is returned, that it is publicly sourced, and how to sequence it relative to other tools. No output schema is necessary for this simple call.

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?

The input schema has zero parameters, so there is no parameter burden. The description still adds value by listing the semantic content categories an agent can expect, such as services, pricing, and service area.

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 clearly identifies the resource ('Garage Doorman') and enumerates the exact fact categories returned: what it does, phone number, opening hours, towns served, services, and pricing. It is easily distinguishable from siblings like fetch, search, and request_quote because it is specifically the business-facts lookup.

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?

'Call this first' is an explicit usage directive telling the agent to invoke this tool before alternatives. However, it does not explicitly state when not to use fetch, search, or request_quote, so some exclusion guidance is missing.

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