list_emails

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

There are no annotations, so the description must carry the behavioral burden. The description indicates this is a read-only listing operation and adds important access context, but it does not explicitly state that no changes are made, nor does it describe behavior under missing authentication or empty results. This is acceptable for a simple list tool, but not fully transparent.

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 well-structured. It leads with the core purpose in one clear sentence, then provides the necessary access prerequisite in a separate paragraph. No filler or redundant content is present.

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 zero-parameter read-only tool, the description is largely complete: it states exactly what the tool returns and the access conditions required. It does not specify the return format in detail, but 'list all email addresses' reasonably implies an array of email addresses, and there is no output schema to explain.

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 tool has zero parameters and the schema describes this completely. With 100% schema coverage and no parameters to clarify, the description does not need to explain parameter meaning; the baseline of 4 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 clearly states a specific action ('List all email addresses') and resource ('associated with the authenticated account'). It is easily distinguished from sibling tools like remove_email, set_primary_email, and start_add_email because no other tool claims to list existing email addresses.

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 provides clear context for when the tool can be used by explaining the authentication prerequisite: a Proof account is required, along with either a PROOF_API_KEY or signing in via start_login. It does not explicitly contrast with alternatives, but no sibling tool offers the same listing functionality, so the usage context is sufficiently clear.

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