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

Annotations already declare non-readOnly, idempotent, non-destructive, closed-world, so the safety profile is covered. The description adds genuinely non-obvious behavior: the API key is returned exactly once (unrecoverable later) and identical requests are deduplicated for 24 hours. It does not say whether business creation is reversible or what an error/duplicate returns, so it stops short of full disclosure.

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?

Three tight sentences with no filler, and the workflow position and no-auth fact are front-loaded. The opening 'Create the business.' mildly duplicates the following sentence, a small redundancy in an otherwise efficient block.

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 an 8-parameter creation tool with no output schema, the description covers the starting-point context and idempotency but not the return payload beyond the API key — notably it never mentions that a business ID comes back, which the agent needs for subsequent sibling calls. Required-field expectations (timezone format, notify destinations) are also unaddressed.

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 13% — only idempotencyKey is documented in the schema, and the description largely restates that same idempotency guidance rather than adding to it. The seven other parameters (name, timezone, ownerEmail, ownerPhone, notify, website, vertical), including all three required ones, get no explanation of format, expectations, or effect, and the description does not compensate for that coverage gap.

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 concrete verb and resource ('Create a RingKit business') plus an important secondary effect ('and its first API key, returned once'). The parenthetical gloss ('pay-per-minute AI phone receptionist') tells an agent what a business is, and the 'first API key' qualifier distinguishes it from the sibling ringkit_create_api_key.

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?

'Step 1' plus 'No auth needed: this is how an agent starts' clearly signals this is the entry point of the flow, which is genuine when-to-use guidance. It never names an explicit exclusion or points to the follow-on tools (ringkit_create_api_key, ringkit_complete_onboarding), so routing beyond the first step is left implicit.

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