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

Annotations already declare readOnly, non-destructive, and non-idempotent, so the safety profile is covered. The description adds genuinely new context: the call blocks while waiting, it is free, and it filters the response down to just the code and link. It does not disclose what happens on timeout expiry, which is the remaining gap.

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 tight sentences with no filler; the core behavior is front-loaded and the cost/prerequisite fragment is short. Minor redundancy in restating required inputs the schema already marks as required, but nothing bloats the definition.

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?

With no output schema the description carries the burden of return values, and it does say only the code and link come back. But for a blocking, timeout-bounded wait tool it never states the failure/timeout outcome, and the 'after' rationale (re-polling without re-seeing messages) is left entirely to the schema.

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 all six parameters including the timeout bounds and the after/from/subject_contains filters are already documented in the schema. The description only restates that inbox_id and secret are required, adding no 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?

The description states a specific verb ('wait for a message') plus the resource (a message carrying a verification code or link) and pins down the return shape ('only the code and the link'). That output-filtering detail implicitly distinguishes it from siblings like wait_for_message and read_message, though no sibling is named outright.

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?

'Free; needs the inbox id and secret' supplies a cost property and prerequisites, which is useful. However, it never says when to pick this over wait_for_message or read_message, nor when not to use it (e.g. for non-OTP mail), so usage is only implied.

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