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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered. The description adds no further behavior such as what happens for an unknown or unverified id, so it only meets the minimum bar given annotation coverage.

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 short sentence, front-loaded with the action and resource, and the trailing clause routes the agent to the correct source of ids. Nothing wasted.

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 single-parameter, read-only getter with no output schema, it says what is fetched, by which identifier, and where that identifier originates. The only gap is no hint about the shape of the returned email record or error behavior.

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%, so the description must carry the id semantics; it does partially by stating the id comes from list_verified_emails. It does not explain the integer/positive constraint, which is left to the schema's type keywords.

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?

States a specific verb and resource ('Fetch one verified email address by id') and names the sibling collection it complements ('from list_verified_emails'), which separates it from list_verified_emails and get_verified_phone without opening a schema.

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?

'from list_verified_emails' tells the agent where the required id comes from, which is the key usage context for a getter-by-id. It stops short of stating when not to use it (e.g. when you want all addresses, use list_verified_emails).

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