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

Annotations only flag it as non-read-only, non-idempotent, open-world. The description adds genuinely useful behavior: the address is inert until a code is confirmed by email, and the number of addresses is capped by the tariff. It stops short of saying what happens on a duplicate address or a quota-exceeded failure.

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?

Three short sentences, front-loaded with the action and then the two most important caveats (pending confirmation, tariff cap). No filler, though the middle sentence could be tighter.

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 two-parameter mutation with no output schema, the description covers the essential lifecycle (pending until confirmed) and a real constraint (tariff limit). It lacks error/duplicate handling, but the core information an agent needs is present.

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 both quiz_id and email are already documented in the schema. The description adds no syntax, format, or constraint detail beyond that, so the baseline 3 applies.

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+resource: adding an email address that receives notification copies for the quiz author. It implicitly differentiates from siblings like confirm_quiz_email_recipient and toggle_quiz_email_recipient by describing the add step of the lifecycle, though it never names them 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?

Usage context is implied (you add an address when you want the author to be notified), but there is no explicit 'use this instead of X' routing and no mention of the sibling confirm_quiz_email_recipient tool that must be called next. The confirmation requirement is described as behavior, not as a usage directive.

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