importTwilioNumber

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

Annotations already declare readOnlyHint=false and destructiveHint=false, so the agent knows this is a mutating but non-destructive operation. The description adds context about requiring Twilio credentials, which is also present in the schema. It does not disclose side effects, idempotency, or ownership checks, so it adds minimal behavioral value beyond annotations.

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?

The description is a single sentence that front-loads the action and requirement. It contains no redundant information, and the tag is harmless.

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 simple import tool with a nested object schema, the description is adequate but minimal. It doesn't explain the outcome of the import, potential error conditions, or how the imported number will be used (e.g., for later attachment). Given the lack of an output schema, the agent might benefit from more context, but the core operation is clear enough.

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 100%, with clear descriptions for phone_number, account_sid, account_token, and name. The description's mention of 'credentials' loosely maps to the SID and token but adds no detail beyond the schema, so it doesn't enhance parameter understanding.

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 states the action ('Import'), the resource ('existing Twilio number'), and the method ('providing your Twilio credentials'). This distinguishes it from sibling tools like importExotelNumber and importSipTrunk, which target different providers.

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 description implies the use case (importing a Twilio number with credentials) but does not explicitly compare to alternatives or state when not to use it. There is no mention of prerequisites or exclusions, leaving the agent to infer from the tool name and siblings.

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