list_emails

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

Annotations declare readOnlyHint=true, so the safety profile is already covered. The description adds valuable auth context: it needs a Proof account, requires PROOF_API_KEY or an active session via start_login, and notes that a session opens this tool. However, it doesn't disclose return format, pagination, or whether it filters by profile — modest value beyond annotations.

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?

Two sentences, front-loaded with the core action followed by the access constraint. No wasted words, though the auth sentence is slightly dense and could be split for a callout.

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 simple zero-param list tool with no output schema, the description covers what it does and the prerequisite auth setup. It lacks any note on return shape (e.g., list vs paginated) or ordering, but that's a minor gap given the simplicity and annotations.

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?

Zero parameters, so baseline 4 applies. The description correctly implies no filtering arguments are needed, and the schema has 100% coverage on an empty object. No missed parameter documentation.

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 (List) and resource (email addresses) scoped to the authenticated account. An agent can immediately tell what it returns and distinguish it from siblings like list_phones or list_circles.

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?

No explicit when-to-use or when-not-to-use guidance. The access note implies this is a read operation on the current account, but nothing distinguishes it from alternatives or states prerequisites beyond the auth requirement.

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