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

Annotations are absent, so the description carries the burden. It discloses that the operation 'may require 2FA verification' and mentions authentication requirements, which is useful. However, it does not specify the effect on the account, reversibility, or what happens if the phone is primary. Lack of output schema also limits info.

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 concise and front-loaded: the core action is in the first sentence, followed by an access note. The access note is somewhat verbose but relevant. No wasted words.

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 tool with one parameter, the description covers the core, but the 2FA requirement and authentication steps are important and included. However, without annotations, it misses potential details like idempotency, error cases, or impact on primary phone, which could be critical 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?

The schema covers 100% of parameters with the description 'Phone record ID' for the id parameter. The description doesn't add much beyond that, but the schema is adequate. 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 verb 'Remove', the resource 'phone number from the account', and the identifier 'by ID'. It is distinguishable from sibling tools like remove_email, remove_challenger, etc., though it doesn't explicitly differentiate. However, the name itself is clear enough.

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: removing a phone number by ID. It mentions a prerequisite: needing a Proof account and authentication. However, it doesn't explicitly state when NOT to use it or name alternative tools, but the context is sufficient.

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