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

Annotations already declare readOnlyHint=false, openWorldHint=true, idempotentHint=false and destructiveHint=false, so the mutation profile is covered. The description adds genuinely new behavior with 'short-lived', signaling the code expires and that calling again likely re-issues it, but it omits rate limiting, whether prior codes are invalidated, and any delivery-failure behavior.

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?

A single front-loaded sentence with no filler or redundancy; the key fact ('short-lived verification code') comes first. Brevity tips into under-specification, but there is no wasted wording to trim.

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 should say what the agent receives and what to do next, and it does not. The expiration hint partially compensates, but for a two-required-param, fully undocumented flow step, an agent is left guessing about the session token and the follow-up confirm call.

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 0% for two required parameters, so the description carries the full burden and largely fails: 'search session' loosely hints at what sessionToken represents, but nothing explains the token's origin, lifetime, or relationship to the email. Neither parameter is meaningfully clarified beyond its type.

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 a specific verb ('Send') with a specific artifact ('a short-lived verification code') scoped to 'the search session', which is clear on its own. It implicitly differentiates from confirm_email_verification by framing this as the code-issuing step, but it never names that sibling, so the distinction is left for the agent to infer.

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?

There is no when-to-use guidance, no prerequisites, and no mention of the confirm_email_verification sibling that logically follows this call. The only signal is 'for the search session', which hints at a preconditions context but does not state one.

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