create_phone_number_route

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

Annotations already declare readOnlyHint=false, destructiveHint=false, idempotentHint=false and openWorldHint=true, so the safety profile is carried by structured data and the description does not contradict it. However, the description adds nothing on top: it does not mention that credentials (Account SID/token, Exotel keys, region config) are required, that repeated calls are non-idempotent, or what side effects occur on the workspace.

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 words are technically waste-free, but this is under-specification rather than conciseness: a 19-parameter, multi-provider onboarding tool cannot be adequately framed in a bare noun phrase. There is no front-loaded scope or context for the agent to anchor on.

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?

Given 19 parameters, zero required fields, a provider-variant schema (Twilio vs Exotel vs SIP trunk, plus region and media-encryption options), and no output schema, the description supplies none of the orientation an agent needs. It does not explain that this provisions a phone number route, which credential set applies, or what happens on success or failure.

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 description mentions no parameters at all despite 19 of them and only 58% schema description coverage. Key choices such as provider, enable_sms, region_config, inbound/outbound trunk config, and the deprecated supports_inbound/supports_outbound flags are left entirely to the schema, with several fields (agent_id, provider, applet_url, api_subdomain, account_auth_token) undocumented in both places.

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?

"Import Phone Number" essentially restates the tool name (create_phone_number_route) with a different verb; it is close to a tautology. It gives no indication of scope, such as which provider (Twilio, Exotel, SIP trunk) is being onboarded or what 'import' means versus a plain create, so an agent cannot distinguish it from siblings like update_phone_number_route or list_phone_numbers_route on the basis of the description alone.

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?

There is no when-to-use guidance whatsoever: no mention of prerequisites, of the alternative tools (update_phone_number_route, delete_phone_number_route, list_phone_numbers_route), or of the conditions that select this route. Nothing in the description helps an agent decide between this and any sibling.

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