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

Annotations already disclose that this is a non-read-only, non-destructive, non-idempotent mutation. The description adds important behavioral context beyond annotations by warning that incoming call routing changes and that carrier webhook configuration is a separate step.

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?

Two tightly written sentences with the core action front-loaded and a useful behavioral caveat immediately after. No wasted language.

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 the rich schema and existing annotations, the description covers the key operational context: what is bound, what changes, and the separate webhook prerequisite. It does not describe the response or permission requirements, but it is largely sufficient for correct invocation.

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 the schema already documents the number format, provider enum, region, and assistant_id constraints. The description reinforces that the number is a carrier number and the target is a workspace assistant, but adds no format or usage semantics beyond the structured fields.

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: 'Bind an existing carrier number to a workspace assistant.' This clearly distinguishes the operation from sibling tools such as unbind_number and list_numbers.

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?

Provides clear context that the number must already exist and that this changes incoming call routing, plus the prerequisite to configure the carrier webhook separately. It does not explicitly name alternatives or exclusions such as when to use unbind_number, but the usage context is clear.

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