twilio_check_verify

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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and openWorld, so safety is covered. The description adds essentially nothing beyond that: it does not state what a failed check looks like (error vs approved/denied status), whether the verification code is consumed, or whether attempt limits/rate limits apply — the details an agent most needs for a verification endpoint.

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?

One sentence, front-loaded with the verb and resource, with no filler. It is short enough that nothing is wasted, though the brevity is partly the source of the gaps elsewhere.

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 5-parameter, all-required tool with no output schema and low schema coverage, the description should explain the credential/identifier params and what the check returns. Neither is present, so an agent cannot call it correctly without external Twilio knowledge.

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 only 20% (only 'code' is documented), so the description carries the burden — yet it says nothing about account_sid, auth_token, service_sid, or 'to'. The agent is left to guess that 'to' is the phone number being verified and that the SIDs are Twilio credentials/resources.

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 pairs the verb 'Check' with a specific resource ('a verification code submitted by a user') and names the Twilio Verify service, so an agent understands it validates an OTP rather than sending one. It does not explicitly name the sibling it complements (twilio_send_verify), so it stops short of a 5.

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?

Usage is implied by 'submitted by a user', which frames the check as the follow-up step in the Verify flow, but there is no explicit when-to-use/when-not or reference to twilio_send_verify as the prerequisite step. The agent must infer the pairing from the description.

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