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

Annotations declare openWorldHint=true, idempotentHint=false and destructiveHint=false, but the description adds the operationally critical fact that this is not a preview: a live receptionist is created and a real number is provisioned on the account, so the agent knows repeating it is not harmless. It also adds the owner-only authorization constraint, which annotations do not encode.

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 action and its automatic number assignment, then constraints. Slight redundancy between 'REAL ACTION, not a preview' and 'a live receptionist is created and a real phone number is assigned', but that emphasis is arguably justified for a tool with real-world side effects.

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?

No output schema and no parameter documentation, but the description covers the things an agent most needs before a real-action onboarding mutation: authorization, confirmation protocol, and the fact that a number is provisioned. Missing only return-value expectations and where to source voice options.

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 0% with no per-property descriptions, so the description is the only source: it enumerates name, call-handling instructions, greeting and voice, which maps the four required params. However, it adds no semantic detail — voice format/enum (getAvailableVoices exists as a sibling but is not referenced), greeting length, or whether voice/greeting accept nulls despite being required.

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 ('Create the first receptionist') plus an unusual side effect handled automatically ('assign it a phone number'). The word 'first' plus the note that the user never picks the number separately distinguishes it from the general updateAgent/listAgents siblings and from the other onboarding_* tools.

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?

Gives a clear precondition ('Owner only') and an explicit procedural instruction ('Right before calling, show the user the exact change and get their explicit confirmation'). It does not name the alternative path (e.g. onboarding_complete_receptionist_setup or updateAgent for later edits), so routing guidance is strong but not exhaustive.

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