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

The description discloses the key side effect of the first call (emailing six digits) and the second-call verification behavior, going beyond the annotations' simple readOnly/idempotent/destructive flags. It does not cover code expiry or failure modes, but the important behavioral traits are present.

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 description is compact and front-loaded with the trigger condition, then walks through the two-step flow without wasted words. It could be slightly cleaner, but every sentence contributes to correct usage.

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?

The description covers the essential two-phase flow and parameter roles, but there is ambiguity around access_token: the description implies it is needed for the first call while the schema marks only item_id as required. It also omits return behavior and error handling, which matters for a multi-step verification tool with no output 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?

The description maps item_id to the target item, access_token to the first call that sends the code, and code to the second verification call. This adds meaning to item_id, which lacks a schema description, and clarifies how the code and access_token relate to the workflow.

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 the tool's purpose: verify a known customer by emailing a six-digit code and then confirming the code. It gives a specific trigger ('identity.recognised is weak') and explains the two-phase flow, which distinguishes it from siblings like acknowledge_receipt or send_message.

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?

The description gives an explicit when-to-use condition: when identity.recognised is weak and the person supplied an email of a known customer. It also spells out the exact call sequence, including the code round-trip, but it does not mention alternatives or exclusions.

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