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

Annotations only declare destructiveHint=true/readOnlyHint=false, but the description enumerates the full blast radius: revoked proofs and consents, declined pending confirmations, flagged approver-less setups, deleted record and messenger links, other devices signed out, new primary phone named. It also states irreversibility and auth requirements, well beyond the 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?

Long but dense and front-loaded: purpose first, then prerequisite, consequences, refusals, and auth. Every clause carries operational information, though the multi-clause consequence sentence is heavy and could be split for readability.

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 destructive single-param tool with no output schema and minimal annotations, the description supplies prerequisite flow, full side-effect list, refusal conditions, and authentication instructions. An agent has everything needed to invoke it correctly.

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 coverage is 100% and already documents the single 'id' parameter, so the baseline is 3. The description adds context by tying the id to the 2FA 'targets [this phone id]' flow, clarifying how the parameter participates in the prerequisite step.

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 ('Remove a phone number from the account') and immediately distinguishes it from siblings like remove_email, set_primary_phone, and list_phones. An agent can identify the operation without opening the schema.

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?

Gives the explicit prerequisite (start_2fa_for_action with action_type phone_remove and targets [this phone id]) and three explicit refusal conditions (number signed in with, only sign-in method, last phone while circles are active) with the circles_need_phone remedy. Nothing about when this is callable is left to inference.

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