retell_import_phone_number

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

No annotations are provided, so the description carries the full burden. It is very thin: it does not disclose that this is a write/mutation operation, whether it creates a new phone number resource, any permissions or prerequisites (e.g., SIP trunk authentication), idempotency, or the response format. The optional agent binding is mentioned but side effects are otherwise opaque.

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 core purpose and includes the key optional capability. Every word earns its place; there is no redundancy or filler.

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 tool with 7 parameters, no output schema, and no annotations, the one-sentence description is insufficient. It doesn't cover prerequisites, what happens after import, or how it differs from retell_create_phone_number. An agent would need more context to select and invoke this tool confidently.

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%, so all parameters have meaning. The description adds minimal context by framing them under 'custom telephony (SIP trunk)' and 'optionally bind agents,' but it doesn't explain parameter relationships or anything beyond the schema. Baseline 3 is appropriate.

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 tool imports a phone number from the user's own custom telephony (SIP trunk) and optionally binds agents. The verb 'Import' is specific and the resource 'phone number' is identified, distinguishing it from sibling tools like retell_create_phone_number by specifying the source as a custom SIP trunk.

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 provides clear context for when to use this tool: when importing a number from a custom SIP trunk. It doesn't explicitly name alternatives or exclusions, but the phrasing implies this is for existing custom telephony setups. It could be stronger with an explicit contrast to retell_create_phone_number for Retell-provisioned numbers.

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