Confirm Phone Verification

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

Annotations mark it as non-read-only, idempotent, non-destructive, and open-world; the description adds the important error paths (PHONE_CODE_INVALID, emailVerified:false) and the retry behavior, though it doesn't mention rate limits or what exactly gets mutated beyond verification state.

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 paragraph is dense but front-loaded with the primary action, then success/failure handling; every sentence carries actionable information with no 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 single-parameter verification tool with no output schema, it covers success, error, and follow-up paths well; only minor gaps like response shape or retry scope remain.

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 the code parameter is fully described there; the description only says 'the code the user received', adding no format or casing detail beyond the schema.

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 it verifies the account's phone number using the code from send_phone_verification_code, a specific verb and resource that distinguishes it from the sibling email verification tool.

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?

It explicitly says when to use it, what to do on success (retry the failed operation), and how to handle email verification and invalid codes, naming the exact sibling tools to call.

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